MediaTek announces Helio P10 and MT6753 arrives in shipping devices

MediaTek has announced Helio P10 (MT6755), a performance mid-range smartphone SoC that is the successor of MT6752. Featuring an octa-core Cortex-A53 configuration, Helio P10 improves upon MT6752 by using TSMC's new 28HPC+ manufacturing process, which delivers power efficiency and performance improvements while remaining relatively cost-effective. It can reach a higher maximum CPU clock speed up to 2 GHz and upgrades the GPU to a Mali-T860 MP2. It is expected to be commercially available in end devices by the end of 2015.

Features shared with Helio-X10

The new SoC  incorporates a few features from Helio X10 (MT6795), MediaTek's current high-end offering, including dual ISPs with 21MP camera support and improved capture capability, as well as improved audio quality.

Otherwise, the SoC has significant similarities to MediaTek's MT6752 which it succeeds, most likely including a 32-bit external memory interface, which keeps SoC cost and phone PCB cost down. With MT6752, MediaTek already demonstrated the ability to achieve memory performance adequate for a 1080p device within the constraints of a 32-bit memory interface.

The 28HPC+ process is an upgrade of the existing 28HPC (high-performance compact) process (which is also relatively new, used by Allwinner's A83T and other SoCs), which improves performance and cost relative to the established 28HPM (high-performance mobile) process. Existing MediaTek chips like MT6752 and MT6795 most likely use 28HPM, which is established and has also been used for previous-generation SoCs such as MT6592 and Snapdragon 801/805.

MediaTek migrating to big.LITTLE CPU configurations in new SoCs

A significant departure from existing octa-core MediaTek SoCs such as MT6752 and Helio X10 (MT6795) is the pseudo-big.LITTLE CPU configuration, whereby one cluster of four Cortex-A53 cores is clocked at a higher frequency (up to 2 GHz in this case), while the second of cluster Cortex-A53 cores is optimized for lower frequencies, being clocked at a lower maximum frequency (1.1 GHz according to AnandTech).

Together with the previously announced high-end Helio X20 (MT6797) and tablet/Chromebook-oriented chips such as MT8173, Helio P10 marks a migration to (pseudo-)big.LITTLE, hierarchical CPU designs at MediaTek. While symmetrical octa-core designs such as MT6752 and MT6795 reach very high multi-core processing power by allowing all cores to run at the maximum frequency, there are signs that this configuration impacts power efficiency for tasks that require less CPU power, which can be run on power-optimized low-frequency cores.

In practice, this may be reflected in somewhat mediocre standby battery life for smartphones using MT6752 or MT6795, even though power efficiency for demanding tasks that utilize all cores is likely to be pretty good.

Budget mid-range MT6753 reaches end-market

Meanwhile, MediaTek's previously announced MT6753, which is a cost-effective budget mid-range SoC, has arrived in commercially shipping device in the form of Meizu M2 Note. Despite the name chosen by Meizu, the new model actually has lower performance than the existing Meizu M1 Note, because the MT6753  is a less costly, lower end chip when compared to to the MT6752 inside the M1 Note, with considerably slower maximum CPU speeds for the eight CPU cores, as well as a lower performance GPU. There are also signs that the memory interface and the actual memory frequency used by the M2 Note is slower. The lower cost of the MT6753 platform is reflected in the low selling price of the Meizu M2 Note.

MT6753 implements several cost-reducing features, including a lower maximum clock speed (reported to be 1.3 GHz for the M2 Note), most likely associated with a cheaper manufacturing process (either 28LP or 28HPC) than the 28HPM process of the MT6752. A significant factor for lower performance is likely to be a reduced size of the L2 CPU cache inside the MT6753. MT6753 is likely to become a significant volume driver in MediaTek's 4G product line.

However, early Geekbench entries for the Meizu M2 Note suggest that the CPU cores of the MT6753 SoC used in this model are mostly unable to reach the planned clock frequency. The Geekbench results are mostly consistent with an average maximum CPU clock speed of about 1.1 GHz, significantly lower than the 1.3 GHz reported by the OS and the 1.5 GHz mentioned when the MT6753 was originally announced a few months ago. My following blog article about the use of AArch64 provides more details on this subject.

MT6753 has lower-performance GPU than MT6752

MT6753 also has a significantly lower-performance and smaller GPU (Mali-T720 MP3), compared to the Mali-T760 MP2 inside MT6752. MT6753 marks the first Mali implementation with three pixel processing cores; previous Mali GPUs either had one, two, four, six or eight pixel processing cores, Most likely, Mali-T720 does not have the memory bandwidth usage optimization that are present in Mali-T760, which together with the more limited pixel processing throughput means that devices with a 1080p display such as the Meizu M2 Note may be impacted in terms of 1080p game performance and power efficiency for graphics-intensive operations.

World modem support in new MediaTek platforms

All new MediaTek SoCs (including Helio P10 (MT6755), MT6753, the low-end quad-core MT6735 and the announced high-end Helio X20 (MT6797)) have world-modem support, facilitating compatibility with more cellular networks used worldwide, including legacy CDMA networks in the US and other countries. This makes MediaTek SoCs more attractive to smartphone manufacturers targeting multiple or worldwide markets.

Sources: MediaTek (Helio P10 announcement), AnandTech (Helio P10 article)

Updated 6 June 2015.

HiSilicon introduces Kirin 930/935, a performance-oriented Cortex-A53-based SoC

Huawei has introduced the Huawei P8 and P8max smartphones, featuring the Kirin 930 and Kirin 935 SoCs from Huawei's  HiSilicon semiconductor division. The octa-core Kirin 930 SoC is a performance-oriented SoC featuring only Cortex-A53 CPU cores. With a maximum clock frequency in excess of 2.0 GHz, it bears similarities to MediaTek's MT6795, but the use of a pseudo big.LITTLE configuration (four Cortex-A53 cores clocked up to 2.0 GHz and four Cortex-A53 cores clocked up to 1.5 GHz, for a total of eight cores) is reminiscent of Qualcomm's midrange Snapdragon 615 SoC, which runs at lower clock frequencies.

Huawei also introduced high-end models of both the P8 and P8max with larger storage capacity featuring the Kirin 935 SoC, which is a higher-clocked version of Kirin 930. The Huawei P8max is a smartphone with an unusually large 6.8" display.

SoC is targeted at performance-oriented devices

The Huawei P8 models are higher-priced performance-oriented smartphones, and the characteristics of the SoC match this segment. Apart from the high maximum clock speed of the Cortex-A53 cores, the external RAM interface is likely to be a dual-channel 32-bit configuration like previous performance-oriented SoCs from HiSilicon. Presentation materials from Huawei describe the Cortex-A53 cores in the faster cluster of four CPUs as being of a special, performance-enhanced type, which probably reflects the application of ARM's PoP core-hardening technology whereby the core is optimized for running at a specific frequency and a particular power profile, trading performance against die size. The process technology used is likely to be TSMC's proven 28HPM process.

The SoC is reminiscent of MediaTek's recently introduced MT6795 (Helio-X), which also targets the performance segment with an octa-core Cortex-A53 CPU configuration. MediaTek's SoC has been reported to have been adopted by competitors of Huawei such as HTC and Xiaomi.

Previous generation Mali-T628 MP4 GPU used

Rather than using an updated current-generation GPU like Mali-T760, the specs sheet for the P8max indicates the Kirin 930/935 SoCs continue to use the Mali-T628 MP4 GPU that was previously used in the Kirin 920 SoC. This GPU core is not known for great power efficiency, although there are suggestions that the more efficient Mali-T760 (which features memory bandwidth optimizations) has a relatively high silicon area and cost.

HiSilicon's new SoC line-up uses only Cortex-A53 CPU cores

Apart from Kirin 930, HiSilicon has also introduced the Kirin 620 SoC, which is an octa-core Cortex-A53 based SoC for the cost-sensitive segment, clocked up to 1.2 GHz and with a single-channel memory interface. This means Huawei now has in-house Cortex-A53-based SoCs suitable for most of its smartphone product range.

Sources: Huawei (P8 announcement), Huawei (P8max announcement), AnandTech (Huawei P8 announcement article)

Updated 17 April 2015.

Qualcomm's Snapdragon 808 fixes flaws of Snapdragon 810

Snapdragon 808 (MSM8992) is a performance-oriented SoC that Qualcomm announced last year together with Snapdragon 810. It has similarities to Snapdragon 810 (MSM8994), including the use of ARM Cortex-A57 CPU cores and Cortex-A53 cores in a big.LITTLE configuration. Snapdragon 808 appears to fix some of the performance flaws that are apparent in Snapdragon 810, especially the memory subsystem, while being significantly less costly.

Snapdragon 808 features

Features and differences with Snapdragon 810 include:

• Snapdragon 808 has only two Cortex-A57 cores (revision r1p2) compared to four Cortex-A57 cores (revision rp1p1) for Snapdragon 810. Both contain four Cortex-A53 cores.
• Snapdagon 808 has a more economical dual-channel LPDDR3 memory interface, compared to the LPDDR4 interface of Snapdragon 810.
• Snapdragon 808 has an Adreno 418 GPU, compared to Adreno 420 in Snapdragon 810, presumably with somewhat lower performance.
• Manufactured on TSMC's 20 nm process, the same as Snapdragon 810.
• 4K resolution video playback (H.264/H.265), on-device display resolution up to 2560x1600 (Snapdragon 810 theoretically supports 4K on-device display resolution, but all currently announced smartphones using Snapdragon 810 are limited to a resolution of 1920x1080).

 

Early benchmark results suggest Snapdragon 808 fixes performance flaws of Snapdragon 810

Early benchmarks for Snapdragon 808 have already appeared on the Geekbench Browser. We can compare Snapdragon 808's single-core performance with Snapdragon 810 and Exynos 7420, all of which run in AArch64 mode in the published benchmark results.

To reduce the impact of thermal throttling, the best Geekbench subtest results for a given device have been collected and combined in the table below. I have made an attempt to estimate the actual maximum clock speed of the Cortex-A57 cores during the benchmarks, partly based on the maximum frequency reported by Geekbench when it appears to apply to the "big" cores and not the "LITTLE" cores.

SoC          "big" CPU                    Arch     JPEG (int)  Lua (int)   Mandelb. (float)
                                                   Comp. IPC         IPC         IPC

MSM8992      2 x 1.69? GHz Cortex-A57r1p2 AArch64  1257  1.96  1385  1.99  1031  1.79
MSM8994      4 x 1.8? GHz Cortex-A57r1p1  AArch64  1358  1.96  1283  1.73  1100  1.79
Exynos 7420  4 x 1.97 GHz Cortex-A57r1p0  AArch64  1486  1.96  1409  1.74  1198  1.78

MT6795       8 x 1.95 GHz Cortex-A53r0p2  AArch64  1026  1.37  1053  1.31   823  1.24
MT6795T      8 x 2.16 GHz Cortex-A53r0p2  AArch64  1128  1.36  1173  1.32   912  1.24

The IPC figures are calibrated on the Cortex-A7 core, whose IPC is fixed at 1.00. Fixing the maximum cock speed to 1.8 GHz for the MSM8994 (Snapdragon 810) results (based on HTC One M9 entries) and at 1.69 GHz for the MSM8992 (Snapdragon 808) produces similar IPC figures for the JPEG Compress integer test and the Mandelbrot floating point test, making them reasonably plausible. The best Lua subtest result for the MSM8992 shows a higher IPC, which may reflect improved L2 cache performance in the MSM8992, which uses a later revision of the Cortex-A57 core.

The single-core CPU performance results show no suprises, with Snapdragon 808 showing good performance that is slightly lower than Snapdragon 810, proportional to the lower maximum clock frequency in the tested devices. However, the Lua test shows higher performance with Snapdragon 808, which is especially true for the multi-core test (results not shown), where Snapdragon 810 seems to be limited to a score of about 1200 with little gain when compared to single-core performance, while Snapdragon 808 consistently scores in the region of 4000.

Memory subsystem performs much better than Snapdragon 810

The following table lists Geekbench scores for some memory-dependent tests. 

SoC          "big" CPU                    Arch     Stream Copy  SGEMM SFFT  SGEMM SFFT
                                                   Single Multi             Multi Multi
MSM8992      2 x 1.69? GHz Cortex-A57r1p2 AArch64  1527   1733   767  1126  1678  2946
MSM8994      4 x 1.8? GHz Cortex-A57r1p1  AArch64  1428   1838   741  1009  1870  3649
Exynos 7420  4 x 1.97 GHz Cortex-A57r1p0  AArch64  2003   2622   957  1363  2888  5014

MT6795       8 x 1.95 GHz Cortex-A53r0p2  AArch64  1356   2068   484   618  1542  4764
MT6795T      8 x 2.16 GHz Cortex-A53r0p2  AArch64  1350   2140   529   694  1659  5333

Notably, Snapdragon 808 delivers memory performance similar to Snapdragon 810 at much lower cost, despite using only a regular LPDDR3 memory interface, as compared to the Snapdragon 810's LPDDR4 memory interface which in theory delivers almost twice the bandwidth. This provides clear evidence that the Snapdragon 810's memory interface is still flawed, while that of Snapdragon 808 is much more optimized. Snapdragon 808 even beats Snapdragon 810 in the single-core SGEMM and SFFT test, despite running at a lower clock speed, which probably also reflects a more optimized and functional memory controller. Even in the multi-core SGEMM and SFFT tests, Snapdragon 808 is not much behind Snapdragon 810 despite having only half the number of CPU cores.

Comparison with MT6795

In the marketplace, Snapdragon 808 may compete with MediaTek's MT6795 (Helios X10), which is a cost-effective performance-segment SoC that only uses Cortex-A53 cores. Comparing Geekbench subtest results, MT6795 scores signficantly lower than Cortex-A57-based SoCs such as Snapdragon 808 in single-core benchmarks, although the gap is not very large except in the SFFT benchmark. The MT6795 does relatively well in multi-core benchmarks, where it beats the Cortex-A57-based Snapdragon 808 and Snapdragon 810 in most cases by a considerable margin, especially in the JPEG Compress, Lua and Mandelbrot tests which are sensitive to the number of CPU cores (multi-core scores have not been listed for these tests in the tables above). As an example, MT6795 scores 8167 in the multi-core JPEG Compress test, twice the score of Snapdragon 808 and almost 40% higher than Snapdragon 810.

Conclusion

Snapdragon 808 appears to be a much more optimized, less flawed SoC product than Snapdragon 810 that may perform similarly or even better than Snapdragon 810 in practical use cases due to the performance flaws present in Snapdragon 810. At the same time, Snapdragon 808 is likely be considerably cheaper. The only caveat is the question of whether excessive heat production makes thermal throttling necessary to the same degree as Snapdragon 810. With only two Cortex-A57 cores, the SoC should be less problematic in this regard.

Source: Geekbench Browser (MSM8992 results), Geekbench Browser (MSM8994 results), Qualcomm (MSM8992 specifications)

Updated 15 March 2015.

Early benchmarks appear for Cortex-A72-based SoC

ARM recently announced the new Cortex-A72 processor core, which is an improved version of the existing high-performance Cortex-A57 processor core.

Alongside the Cortex-A72 CPU core, ARM also announced the CCI-500 interconnect technology as well as the high-end Mali-T880 GPU. Devices incorporating the combination of these technologies are expected to become available in 2016.

However, SoCs using the Cortex-A72 CPU are likely to become available earlier. Qualcomm and MediaTek have both announced SoCs using the Cortex-A72 core with commercial availability in the second half of 2015, suggesting that the CPU core itself is at an advanced stage of introduction. Already, early benchmarks for MediaTek's MT8173 tablet SoC that incorporates the Cortex-A72 have become available.

Cortex-A72 appears to be enhanced version Cortex-A57 optimized for next-generation processes

In its announcement press release from 3 February 2015, ARM claims that more than ten partners have already licensed Cortex-A72, including HiSilicon, MediaTek and Rockchip. Cortex-A72 is based on ARM's ARMv8-A instruction set architecture, and can be combined with the existing Cortex-A53 in a big.LITTLE configuration. Cortex-A72 seems to be positioned as a replacement for Cortex-A57. The similarities with Cortex-A57 are very apparent, for example in the identically sized L1 instruction and data caches, and a feature set that is otherwise very similar.

On a 16 nm FinFET process, the core can sustain operation at speeds up to 2.5 GHz within the constraints of a mobile power envelope (e.g. smartphones), with scalability to higher speeds for larger form-factor devices. However, the first announced devices, such as MediaTek's MT8173, appear to use older processes such as the tried-and-trusted 28 nm HPM process at TSMC, so they are likely to have a lower maximum clock speed.

ARM claims increased performance and power efficiency, although these claims seem to be based on implementation on next-generation processes such as 16 nm FinFET that deliver a significant intrinsic improvement in these metrics. ARM mentions micro-architectural improvements that result in enhancements in floating point, integer and memory performance. When implemented on a 16 nm FinFET process, ARM expects Cortex-A57 to provide 85% higher performance when compared to the Cortex-A57 core on a 20 nm process within a similar smartphone power budget.

Overall, the differences with Cortex-A57 appear to be relatively minor, so that Cortex-A72 is best viewed as an enhanced version of Cortex-A57 that is optimized for next-generation processes such as 16 nm FinFET. Nevertheless, the first SoCs to use the Cortex-A72 core will be manufactured using a less advanced process.

Benchmarks appear for MediaTek's MT8173

MediaTek's MT8173 is a mid-range tablet processor mainly targeting Wi-Fi-only tablets, since it does not have an integrated modem. It has two Cortex-A72 cores and two Cortex-A53 cores in a big.LITTLE configuration. Probably manufactured using the established 28HPM process at TSMC, the maximum clock speed of the Cortex-A57 cores is likely to be lower that the target for 16 nm FinFET, although MediaTek claims a clock speed up to 2.4 GHz, while a much lower frequency is apparent in early benchmarks results.

The chip also features a PowerVR GX6250 GPU, which delivers higher performance than the G6200 GPU used inside MediaTek's existing MT8135 and MT6795.

Recently, early benchmarks for a MT8173 development board have appeared both in the Geekbench Browser and in the results database of GFXBench. The first Geekbench results already appeared in December 2014. The latest set of Geekbench results date from the end of February 2015, although they do show a certain amount variation that may reflect thermal throttling.

Single-core performance good, but not spectacular

As expected, the Geekbench results show good single-core performance, albeit not spectacular. As shown in the following table, singe-core performance is in line with Cortex-A57-based SoCs such as Exynos 5433 and Exynos 7420. It should be noted that the MT8173 test SoC is most likely manufactured at 28 nm with a corresponding relatively low maximum CPU clock speed, while Exynos 5433 and 7420 are manufactured using smaller leading edge processes at Samsung.

SoC          "big" CPU                    Arch     JPEG (int)  Lua (int)   Mandelb. (fp)
                                                   Comp. IPC         IPC         IPC
MT8173       2 x 1.6? GHz Cortex-A72      AArch32  1310  2.13  1380  2.10  1064  1.95
Exynos 5433  4 x 1.80 GHz Cortex-A57r1p0  AArch32  1456  2.10  1397  1.89  1174  1.91
Exynos 7420  4 x 1.97 GHz Cortex-A57r1p0  AArch64  1481  1.97  1409  1.74  1198  1.92

In this table, to determine the IPC index I have made an educated guess about the actual clock speed of MT8173 when running the benchmarks. Geekbench reports a 1.40 GHz clock speed (which probably applies to the Cortex-A53 cores), 1.6 GHz seems to be a good match, providing just a little better IPC than Cortex-A57. Note that Exynos 7420 runs in AArch64 mode, which skews direct IPC comparisons.

Practical implications unclear

Without knowing the exact clock speed of the Cortex-A72 cores, it is hard to draw conclusions about the actual IPC improvement over Cortex-A57. If the MT8173 uses a 28 nm process, the ability to approach the single-core performance of Samsung's Exynos 7420 manufactured using 14 nm FinFET process is impressive. However, although MediaTek demonstrated the MT8173 in an actual tablet at MWC, it is unclear what kind of device the Alps development board in the benchmark entries actually represents, so it remains to be seen whether the benchmarks actually reflect the power budget of a tablet.

The multi-core performance reported is not very impressive, as expected because of the relatively small number of CPU cores. The JPEG Compress multi-core score shows CPU scaling factor of 2.72, which is good and implies utilization of the Cortex-A53 cores. The Mandelbrot floating point benchmark shows similar scaling.

However, the Lua integer benchmark has a very low multi-core scaling factor of 1.41, which is lower than expected, even when allowing for the limited number of cores. For example, MediaTek's MT6795 achieves multi-core scaling of 7.5 in this benchmark, and the Exynos chips range from 3.9 to 5.0. Other chips with a low multi-core scaling factor for Geekbench's Lua subtest include Snapdragon 810 (Cortex-A57-based), MediaTek's MT6595 (Cortex-A17-based) and NVIDIA's Denver-based Tegra-K1 SoC. There are indications that this benchmark test heavily depends on on-chip cache (primarily L2 cache) size and speed.

GPU performance of MT8173's PowerVR GX6250 GPU improves on G6200

The MT8173 test device's GPU performance as shown in GFXBench results database is not overly impressive, but suitable for a mid-range chip and an improvement over the PowerVR G6200 GPU used in other MediaTek SoCs such as MT6595 and MT6795. In the T-Rex Offscreen benchmark, the MT8173 registers a score of 1487, higher than the 1311 of the MT6595 (G6200)-equipped Meizu MX4. In the GFXBench 3.0 low-level tests, alpha blending scores higher than the MT6595 while the other low-level scores are comparable.

Sources: ARM (Cortex-A57 announcement press release), AnandTech (MediaTek MT8173 article), MediaTek (MT8173 announcement), Geekbench Browser (MT8173 test device results), GFXBench (MT8173 test device result)

Updated 10 March 2015.

A deeper look at graphics benchmark results, including GFXBench 3.1 and Basemark X

In this post I will take a closer at graphics benchmark results for different SoCs. I will look beyond just GFXBench (for which a new version has appeared), because the workload tested by well-known GFXBench tests such as T-Rex and Manhattan is not necessarily reflective of the actual gaming experience. Alternative benchmarks exist, such as Basemark X which uses the Unity engine that is commonly used in games.

GFXBench 3.1 released for OpenGL ES 3.1, Snapdragon 805 does well

Kishonti recently released a new version of GFXBench, GFXBench 3.1 for OpenGL ES 3.1, that includes tests for the OpenGL ES 3.1 API standard supported by many recent devices. A few results from the new benchmark tests are already available, with the Adreno 420 GPU inside Snapdragon 805 closing most of the performance gap with the Mali-T760 MP6/MP8 in Samsung's Exynos SoCs in the Manhattan 3.1 test.

                                                      Offscreen Manhattan Manhattan
Device               SoC             GPU              T-Rex        3.0       3.1

NVIDIA Shield Tablet NVIDIA K1-32    Tegra K1 GPU        3692     1979      1443  
HTC One M9           Snapdragon 810  Adreno 430          2732     1413
Galaxy S6 Edge       Exynos 7420     Mali-T760 MP8?      3312     1607       793
Sams. Galaxy Note 4  Snapdragon 805  Adreno 420          2386     1153       773
Samsung Galaxy S6    Exynos 7420     Mali-T760 MP8?      3314     1609       634
Sams. Galaxy Note 4  Exynos 5433     Mali-T760 MP6       2163     1110       436
HTC One M8           Snapdragon 801  Adreno 330          1608      768
Teclast X98 Air      Atom Z3736F     Intel HD            1014      564       307
Google Nexus 10      Exynos 5250     Mali-T604 MP4        818      351       185

NVIDIA's Tegra 32-bit version of Tegra K1 leads (the 64-bit Denver-based version of Tegra K1, and Tegra X1, have not yet been tested). Performance of Snapdragon 805 as implemented in certain models of the Samsung Galaxy Note 4 holds up better in the Manhattan 3.1 test than Samsung's Exynos SoCs with Mali-T760 MP6/MP8. Whereas Exynos 7420 (used in the Galaxy S6) has a clear advantage in existing benchmarks (1609 vs 1153 for Manhattan and 3314 vs 2386 for T-Rex), it loses that advantage in the new Manhattan 3.1 test (although the Galaxy S6 Edge benchmarks result suggests it is still slightly superior). Intel's Baytrail SoCs seem to hold up relatively well looking at the result for an Atom Z3736F-based tablet, albeit at a lower performance level.

GFXBench 3.1 results for Snapdragon 801 and the new Snapdragon 810 are not yet available. However, given the fact that GFXBench appears to generally do well on Snapdragon SoCs, they can be expected to score fairly highly. I'll say more about the apparent advantage for Qualcomm's SoC in GFXBench in the final section of this article.

Basemark X is a useful alternative to GFXBench

Basemark X is a gaming benchmark that utilizes the Unity engine that is commonly used in games, and developer Rightware claims that it actually reflects practical performance in games. Although it does include an on-screen demo, the actual benchmark scores appear to be derived from off-screen rendering at a fixed resolution, so that benchmark results can be compared objectively between different devices.

Previous generation SoCs: MT6582 beats Snapdragon 400 in Basemark X

Taking a look at previous-generation cost-sensitive SoCs, while MediaTek's ubiquitous quad-core 3G SoC MT6582 (which supports Open GL ES 2.0 only, through its Mali-400 MP2 GPU) scores lower than Snapdragon 400 in GFXBench's OpenGL ES 2.0-based T-Rex test (about 230 vs 330), in Basemark X MT6582-based devices score higher than Snapdragon 400 based devices. This is despite the fact that Snapdragon was/is often employed in devices with a considerably higher selling price than MT6582-based devices.

Device               SoC             GPU                 Display*   Medium   High

Samsung SM-G800F     Exynos 3470     Mali-400 MP4        1280x720    7527    2712
Vodafone 985N        MT6582          Mali-400 MP2         960x540    4950    1717
Acer E53             MT6582          Mali-400 MP2        1280x720    4870    1694
Wiko Rainbow         MT6582          Mali-400 MP2        1280x720    4826
Galaxy S3 Neo        Snapdragon 400T Adreno 305          1280x720    4540    1551
Moto G (XT1032)      Snapdragon 400  Adreno 305          1280x720    4440
HTC Desire 816d      Snapdragon 400T Adreno 405          1280x720    4354    1441
Samsung SM-A500F     Snapdragon 410  Adreno 306          1280x720    4132    1900
Samsung SM-A300F     Snapdragon 410  Adreno 306           960x540    4076    1892
Samsung SM-G530H     Snapdragon 410  Adreno 306           960x540    3987    1690
Samsung SM-G800A     Snapdragon 400  Adreno 305          1280x720    3946    1362
HTC Desire 820q      Snapdragon 410  Adreno 306          1280x720    3786

* While Basemark X is independent of display resolution in terms of rendering, the
memory bandwidth used for screen refresh has some impact, giving lower-resolution
devices a small advantage.

Notes: Samsung SM-G800F is the Galaxy S5 Mini (Exynos version), while SM-G800A is a Snapdragon 400 running at the non-standard maximum clock speed of 1.4 GHz; Vodafone 985N is the Vodafone Smart 4 Power; Acer E53 is the Acer Liquid E700; Galaxy S3 Neo runs the Snapdragon 400 SoC at a non-standard maximum speed of 1.4 GHz; HTC Desire 816d runs the Snapdragon 400 SoC at 1.6 GHz; SM-A500F is the Galaxy A5, while SM-A300F is the Galaxy A3; SM-G530H is the Galaxy Grand Prime.

For both the medium detail and high detail settings, MT6582-based devices consistently score higher in Basemark X than Snapdragon 400 and also Snapdragon 410-based devices for the medium detail test, which gives a different picture than the one you get from just looking at GFXBench's T-Rex benchmark

Snapdragon 410 performs worse than Snapdragon 400 in Basemark X medium-detail

Also notable is that Snapdragon 410, which is the successor of the Snapdragon 400 and would normally be expected to improve performance, actually has lower performance in practice as judged by the Basemark X medium detail benchmark. This matches earlier findings of performance flaws in Snapdragon 410. When running the high detail Basemark X benchmark, Snapdragon 410 does better and beats Snapdragon 400.

Mid-range SoCs: Snapdragon 615 and MT6752 closely matched

When running GFXBench, Snapdragon 615 and MT6752 are closely matched, with Snapdragon 615 scoring about 830 to 850 in T-Rex while MT6752 scores just above 870. For T-Rex, devices using MediaTek's prior-generation octa-core MT6592 score in the range 650 to 750. In the OpenGL ES 3.0 API-based Manhattan benchmark, Snapdragon 615 and MT6752 are very closely matched, both scoring around 360. We will also take a look at Basemark X results.

The following table shows Basemark X results for the new competing mid-range SoCs Snapdragon 615, MT6752 and HiSilicon's octa-core Hi6210 (Kirin 620), as well as for the prior-generation octa-core MT6592 from MediaTek.

Device               SoC             GPU                 Display*   Medium   High

Lenovo P70-A         MT6752          Mali-T760 MP2       1280x720   11311 
Meizu M1 Note        MT6752          Mali-T760 MP2       1920x1080  11168    4636
HTC Desire 816G      MT6592          Mali-450 MP4        1280x720   10984
Huawei CHE2-TL00     Hi6210          Mali-450 MP4        1280x720   10546    3439
Oppo R8106           Snapdragon 615  Adreno 405          1920x1080  10277    4846 
HTC Desire 820       Snapdragon 615  Adreno 405          1280x720   10133    4814
Samsung SM-A700FD    Snapdragon 615  Adreno 405          1920x1080  10052    4757
Archos 50C Oxygen    MT6592          Mali-450 MP4        1280x720    9867    3702
HTC Desire 616d      MT6592M         Mali-450 MP4        1280x720    7976    3045

* While Basemark X is independent of display resolution in terms of rendering, the
memory bandwidth used for screen refresh has some impact, giving lower-resolution
devices a small advantage.

Notes: SM-A700FD is the Galaxy A7; Huawei CHE2-TL00 is a new version of the Honor 4X.

When running the standard medium-detail version of Basemark X, MediaTek's MT6752 has  a moderate advantange over Snapdragon 615, while at the high detail setting Snapdragon 615 has a small advantage. Huawei's Kirin 620 performs adequately and just ahead of Snapdragon 615 in the medium detail setting.

MediaTek's prior-generation octa-core MT6592 with Mali-450 MP4 GPU keeps up relatively well in Basemark X,  with certain models (e.g. HTC Desire 816G) actually beating Snapdragon 615 in the medium detail setting.

Performance-oriented SoCs with Basemark X

The following table shows Basemark X results for several performance-oriented mobile SoCs.

Device               SoC             GPU                 Display*   Medium   High

Samsung Galaxy S6    Exynos 7420     Mali-T760 MP6       2560x1440  36017
Galaxy S5 LTE-A      Snapdragon 805  Adreno 420          1920x1080  32685   18334
Google Nexus 6       Snapdragon 805  Adreno 420          2560x1440  30362   20265
Sams. Galaxy Note 4  Snapdragon 805  Adreno 420          2560x1440  31963   21152
Sams. Galaxy Note 4  Exynos 5433     Mali-T760 MP6       2560x1440  29335   19019 

Apple iPad Air 2     Apple A8X       PowerVR Series 6    2048x1536  41700   29239
Google Nexus 9       NVIDIA K1-64    Tegra-K1 GPU        2048x1536  37939   28646
Apple iPad Mini 3    Apple A7        PowerVR Series 6    2048x1536  26499   14780
Teclast X98 Air      Atom Z3736F     Intel HD            2048x1536  14825    7160
Teclast P90HD        Rockchip RK3288 Mali-T764           2048x1536  13053    5645
Onda V989 Core8      Allwinner A80   PowerVR G6230       2048x1536  11004    5724

Meizu MX4 Pro        Exynos 5430     Mali-T628 MP6       1920x1200  25547   12674
Samsung SM-G900A     Snapdragon 801  Adreno 330          1920x1080  25178   11930
Samsung SM-G850F     Exynos 5430     Mali-T628 MP6       1280x720   21872   10666
Meizu MX4            MT6595          PowerVR G6200       1920x1200  17038    7817
Huawei MT7-TL10      Kirin 925       Mali-T624 MP4       1920x1080  15973    6802

* While Basemark X is independent of display resolution in terms of rendering, the
memory bandwidth used for screen refresh has some impact, giving lower-resolution
devices a small advantage.

Notes: SM-G900A is the Samsung Galaxy S5 (US version), Huawei MT7-TL10 is the Huawei Mate 7.

Looking at the ultra-high-end smartphone segment (mostly with a display resolution of 2560x1440), Exynos 7420 provides superior performance in Basemark X. Snapdragon 805 follows, a small distance ahead of Exynos 5433 as used in the Samsung Galaxy Note 4.

In the high-end tablet segment, Apple's iPad Air 2 with the Apple A8X leads, but the Nexus 9 with NVIDIA's Tegra K1 (64-bit version) comes fairly close. Apple's prior generation SoCs also delivers good performance, while Intel's current Baytrail SoC for the tablet market outperforms two high-end chips from established Chinese players in the tablet SoC market, Rockchip's RK3288 and Allwinner A80 Octa.

Mainwhile, in the mainstream performance smartphone segment, Snapdragon 801 (in the past the performance leader in the market) still provides good performance, but is actually just beaten by the 32-bit Exynos 5430 in the Meizu MX4 Pro. The chip is also used in the Galaxy Alpha (for which it provides higher-than-necessary performance given its relatively low screen resolution), while the performance of MediaTek's MT6595 SoC, while not bad, falls short of most other high-end solutions. HiSilicon's Kirin 925 as implemented in the Huawei Mate 7 is just behind.

Conclusion

It appears that just concentrating on GFXBench may give a misleading picture with regard to 3D graphics performance of mobile SoCs. In particular it is apparent that Qualcomm's Snapdragon SoCs consistently do better in GFXBench than in other benchmarks such as Basemark X. This is particularly true for the lower-end Snapdragon 400 and higher-end Snapdragon 800 series; for Snapdragon 615, results are more consistent across different benchmarks.

Basemark X, which utilizes the Unity game engine commonly used in mobile games, may more accurately reflect real-world performance.

Sources: Rightware Power Board (Basemark X benchmark results), GFXBench results database

Updated 5 March 2015: Add Galaxy S6 Edge result for GFXBench 3.1.
Updated 15 March 2015.

New mobile SoCs announced at MWC

At the Mobile World Congress this week, several new mobile SoCs are being announced.

MediaTek announces cost-reduced MT6753 for smartphones

MediaTek anounced two mobile SoCs, the MT6753 for smartphones and the MT8173 for tablets.

The MT6753 appears to be a cost-reduced version of the successful MT6752, equpped with "WorldMode" modem technology. By offering compatibility with the CDMA2000 standard, it gives customers worldwide greater diversity and flexibility in their product layouts, according to MediaTek. Features include an octa-core Cortex-A53 CPU up to 1.5 GHz and a Mali-T720 GPU with an unspecified number of cores. ARM's Mali-T720 GPU is positioned at a significantly lower performance bracket than the Mali-T760 used in the MT6752, positioning the MT6753 below the MT6752 in terms of cost and performance.

The MT6753 is described as being compatible with the previously announced MT6735 for entry-level smartphones. The MT6735 has four Cortex-A53 cores instead of eight but otherwise has a similar configuration with a Mali T720 GPU.

High-performance MT8173 tablet SoC uses small big.LITTLE clusters with Cortex-A72

The MT8173 is a high-performance tablet processor (without integrated modem) that utilizes ARM's new Cortex-A72 core in a big.LITTLE configuration. By using only two Cortex-A72 cores (clocked up to 2.4 GHz) as well as two Cortex-A53 cores, the chip has a lower cost than would be the case with the four-by-four core configuration commonly used for big.LITTLE designs, while still providing good performance.

The Cortex-A72 core, the successor of Cortex-A57, appears to be seeing quick adoption as Qualcomm has already announced performance-segment smartphone SoCs (Snapdragon 618 and 620) featuring the core.

MediaTek has previously used a similar two-by-two big.LITTLE configuration in its MT8135(V) tablet SoC, which has two Cortex-A15 cores and Cortex-A7 cores. This chip was used in Amazon tablets but otherwise did not see much adoption.

Other features include a PowerVR GX6250 GPU, which is part of Imagination's Series 6XT family, with higher performance and efficiency than the G6200 GPU used in chips such as the MT8135 and MT6595.

Other tablet SoCs not yet publicly announced by MediaTek

Meanwhile, tablet product announcements by Lenovo also refer to the MT8161 and MT8165 SoCs, which have not been announced. From the specifications of the Lenovo Tab 2 A8 which is using it, the MT8161 appears to be a tablet SoC without modem with quad-core Cortex-A53 CPU running up to 1.3 GHz, while the MT8165 (used in the Tab 2 A10) is a similar SoC with the CPU running up to 1.5 GHz. The 4G version of the Lenovo tablets come equipped with the MT8735 (Tab 2 A8) and MT8732 (Tab 2 A10). These chips are the tablet versions of the MT6735 and MT6732 smartphone SoCs.

MT6795 renamed to Helio X10

In a closed-door presentation at MWC, MediaTek also presented the Helio X10 smartphone SoC, featuring a 64-bit octa-core CPU up to 2.2 GHz, 120 Hz display refresh rate and H.265 video encode up to 4K2K @ 30 fps. A photograph of a slide taken at the presentation strongly suggests that Helio X10 is nothing other than the delayed MT6795 SoC, whose specifications closely match. Devices using this chip are likely to have already started production. MediaTek also talked about the Helio P series, a high-performance platform, which will make its way into devices before the end of the year.

Qualcomm gives preview of next-generation Snapdragon 820 SoC

In a press release, Qualcomm has given a preview of the Snapdragon 820, which utilizes Qualcomm's new custom 64-bit CPU architecture for mobile devices called Kryo. The chip will start sampling in the second half of 2015 according to Qualcomm, with devices becoming available in 2016. It will be manufactured on a next-generation FinFET process (which probably means TSMC's 16FF+, but Samsung cannot be excluded). In the press release, Qualcomm does not mention whether the chip will conform to ARM's ARMv8 instruction set architecture.

In conjuction with the Snapdragon 820, Qualcomm also announced the Zeroth hardware/software platform focusing on device intelligence features including video and audio recognition techniques (such as visual object and face recognition).

Intel introduces tablet and smartphone SoCs with integrated modem

Intel has finally introduced SoCs with an integrated cellular modem in its Atom system-on-a-chip product line. The former SoFIA platform has been renamed to Atom X3 and features multi-core 64-bit Atom processors with integrated 3G or 4G LTE modem technology. The following products are available:

• Atom X3-C3130, which has dual-core Atom CPU running up to 1.0 GHz and integrates a 3G modem. It features Mali-400 MP2 GPU. Maximum display resolution is 1280x800. It appears to be in the same market segment as MediaTek's previous-generation 3G SoCs such as MT6572 and MT6582 and other SoCs that are already on the market.
• Atom X3-C3230RK, which was developed by Intel partner Rockchip following the agreement announced last year. It has quad-core Atom CPU, integrates a 3G modem and features a Mali-450 MP4 GPU.
• Atom X3-C3440, a quad-core Atom CPU platform that integrates a Cat 6 LTE 4G modem. It has an Mali-T720 MP2 GPU. This product appears to be one that is most likely to succeed in the market.

All feature a 32-bit memory interface with support for LPDDR2 (and DDR3/DDR3L with the X3-C3230RK). These are the first Intel products that have features (such as the integrated modem) that make them specifically suitable for the smartphone market. They also target cellular-enabled tablets.

The 3G products are a little behind the times, and their success is uncertain. It will be interesting observe whether Rockchip was able to develop the X3-C3230RK in time (one would expect Intel to have greater expertise/resources so that the other products will appear on the market first).

One notable fact is that these are among the first SoCs to integrate an ARM GPU core with a non-ARM CPU.

Intel announces first 14 nm Atom SoCs for tablets and all-in-ones

Intel also rolled out its first 14 nm Atom SoCs, the Atom x5 and x7 processor series (formely codenamed Cherry Trail) with  Intel Gen 8 graphics, targeting tablets and small screen all-in-ones.

Intel has also introduced a new stand-alone modem chip, XMM 7360, which support LTE Cat 10 and download speeds up to 450 Mbps, as well as wireless connnectivity products (including WiFi/Bluetooth, GNSS/GPS and NFC solutions).

Sources: MediaTek (MT6753 announcement), MediaTek (MT8173 announcement), Qualcomm (Snapdragon 820/Zeroth platform preview), Intel (MWC announcements), Intel Atom x3 Processor Series Brief

Samsung announces Galaxy S6 with Exynos 7420 SoC manufactured on "14nm" FinFET process

At the Mobile World Congress today (Sunday 1 March), Samsung announced the Galaxy S6 and Galaxy S6 Edge, featuring a numerous improvements over the previous generation Galaxy S5, including a SoC manufactured on Samsung's 14 nm FinFET-based process. The Galaxy S6 is planned to available in 20 countries starting on April 10th, 2015.

New model implement several improvements

The improvements in the new model include the following:

• Exynos 7420 SoC manufactured on 14 nm FinFET process with 20 nm interconnects. The CPU is a big.LITTLE configuration with four Cortex-A57 and four Cortex-A53 cores, similar to Exynos 5433. The maximum clock speeds are 2.1 GHz and 1.5 GHz, respectively. Samsung claims 20% better performance and 35% better efficiency for the new chip when compared to Exynos 5433, which is manufactured using Samsung's 20 nm HKMG process.
• The GPU has been rumoured to be a faster version of the Exynos 5433's Mali-T760 MP6 (either a higher clock rate or an MP8 configuration).
• Early benchmarks indicate a significant increase in CPU and memory performance combined with a measurable increase in GPU performance (which is required because of the higher screen resolution).
• Runs in 64-bit AArch64 mode, which has several advantages, as well as some disadvantages.
• Uses new LPDDR4 SDRAM (3 GB), which has higher memory bandwidth at a given memory bus width due to higher effective clock speeds.
• The cameras have been improved, including greater light gathering capability.
• The 5.1" AMOLED screen's resolution is QHD (2560x1440), which is 77% more pixels than the FullHD (1920x1080) screen in Galaxy S5. The higher CPU, GPU and memory performance are essential to keep pace with increased demands caused by the higher resolution.
• Utilizes the new UFS 2.0 interface for embedded flash memory, providing SSD-like performance according to Samsung.
• Cat 6 LTE mode.
• Touchwiz user-interface on top of 64-bit Android 5.0 is said to be more intuitive and less demanding in terms of processing requirements.

At the same time,  Samsung has dropped the MicroSD slot and the battery is non-removable. The battery capacity is also slightly smaller that of the Galaxy S5.

The Galaxy S6 Edge, like the Galaxy Note 4 Edge, features a screen that curves around the edges. It is priced significantly higher than the Galaxy S6, which will not be cheap either.

Quick ramp of 14nm FinFET process brings challenges to Samsung

The initial 14 nm FinFET process used by Samsung has been reported to use 20 nm interconnects with a 14 nm features size. As such it is more of an evolutionary step from 20 nm than full-blooded 14 nm FinFET would be, comparable to some degree with TSMC's 16FF process.

Still, Samsung will face a huge challenge ramping up the process in sufficient volume and acceptable yield rates to equip the high volume of Galaxy S6's expected. Rumours have mentioned low yield for the process in the recent past as Samsung started ramping up (test) production. Given the massive investment in the new process and non-optimal yield rates, it is unlikely that Samsung will significantly benefit financially from production of the chip in the near-term in terms of gross margin and other chip production-related metrics.

However, the performance lead of the Galaxy S6 made possible by the new chip could have significant positive implications for the sales and financial performance of Samsung's smartphone division, allowing Samsung to recoup some of its investment.

A few months ago, Samsung already signed an agreement with Apple whereby Samsung would supply part of the production capacity for future Apple processors. If this bears fruit it would allow Samsung to recoup more of its investment in 14 nm FinFET technology in the future.

Early benchmark performance impressive

In early benchmarks scores reported in Geekbench's result database, a device that probably is the Galaxy S6 shows impressive performance, well ahead of most existing SoCs and devices. In a direct comparison with an Exynos 5433-equipped Galaxy Note 4, the performance gain is fairly significant for most benchmarks (up to 30% for integer tests, higher for floating point), with a few negative outliers such as SHA2 and the Dijkstra integer subtest. The Dijkstra subtest also scores lower on other 64-bit AArch64 platforms, suggesting it suffers from particular AArch64 features such as the doubled size for pointer storage.

Memory performance is also significantly higher, aided by high clock rate and high amount of bandwidth delivered by the LPDDR4 memory interface, which unlike Qualcomm's Snapdragon 810 does not seem to have serious flaws.

Sources: AnandTech (Samsung annnounces the Galaxy S6 and Galaxy S6 Edge), AnandTech (Samsung Unpacked, MWC 2015 Live Blog), Geekbench Browser (Samsung SM-G925F)

Early benchmarks for MT6795 show high performance, suggest use of eight Cortex-A53 cores

MediaTek originally announced the MT6795, a SoC targeting the premium-level and performance segments of the smartphone market, in July 2014, with expectations of devices being commercially available to end users before the end of 2014. However, the chip was delayed (problems with the memory controller were reported) and competitive benchmark results are only now beginning to surface for the chip.

According to the announcement, the SoC was to have an octa-core CPU configuration with clock speeds up to 2.2 GHz, a strong dual-channel memory interface with support for LPDDR3 up to 933 MHz, 2K (2560x1600) display support. Other reports and information have suggested that it uses a PowerVR G6200 GPU, similar to the one used in MediaTek's MT6595, which can be seen as 32-bit predecessor of the new chip.

Confusion about processor cores, octa-core Cortex-A53 seems likely

The actual CPU cores used inside the MT6795 continue to be source of confusion. Initially understood to be an octa-core Cortex-A53 CPU configuration clocked at a high frequency, later a purported leaked MediaTek product roadmap surfaced that described the MT6795 as a big.LITTLE design that includes Cortex-A57 cores. However, a recent new entry in the Geekbench database suggesst that the chip actually has eight Cortex-A53 cores as originally suspected, as the IPC (instructions per cycle) of the integer and floating point subtests would be hard to reconcile with Cortex-A57 cores being present.

Geekbench results show mixed performance but high overall score

The Geekbench results show strong CPU performance, with the overall score being superior to that of available results for Snapdragon 810, which has a significantly higher cost design but has been plagued by performance issues, although it scores lower than Exynos 5433/Exynos 7 Octa with Cortex-A57 cores as used in the Galaxy Note 4. Note that MT6795 uses a less advanced 28 nm process compared to the 20 nm process used for Snapdragon 810 and Exynos 5433.

Single-score integer performance is not spectacular and below that of the previous generation high-end chips such as Snapdragon 801. Although this is compatible with the use of medium-performance Cortex-A53 cores, integer single-core performance is actually lower than the mid-range MT6752, despite the higher clock rate, pointing to continuing hardware performance problems with the chip. The Dijkstra benchmark result is particular low. This benchmark has a lot of external memory access and likely branches a lot, taxing certain elements of the CPU and SoC that simpler CPU benchmarks do not. It may be affected by the doubled address size in AArch64 mode, either through the increased size of pointer storage or reduced efficiency of the branch prediction unit inside the processor core.

Single core floating point performance in the Mandelbrot benchmark is higher than the MT6752 and actually compatible with the Cortex-A53 core running at 2.1 GHz, close to the originally envisaged maximum clock speed for the MT6795. Multi-core performance in this subtest is impressive, with a score that is higher than most existing SoCs including Exynos 7 Octa, which employs faster Cortex-A57 cores.

Finally, the dual-channel memory interface seems to working reasonably well in the tested revision of the chip/development board, with memory scores consistent with an optimized dual-channel interface, and higher, for example, than those of Exynos 5433. However, they are generally lower than those of the 32-bit MT6595.

One caveat is that the MT6795 entry is running in AArch64 mode, while the other devices were running in AArch32 (32-bit ARMv8) or 32-bit ARMv7 mode.

Average single-core CPU performance, strong multi-core performance

In a direct comparison with the MT6752, which has a comparable CPU configuration but clocked lower and has only a 32-bit memory interface, the MT6795 is only slightly faster, although the MT6795 uses a full 64-bit AArch64 instruction set model, while the tested MT6752 configurations use AArch32 with partial use of ARMv8 features. There are a few anomalous results, including a low score for the MT6795 in the single-core AES benchmark, and as mentioned it also scores significantly lower in the Dijkstra benchmark. Floating point performance is consistently higher for the MT6795 (more than the increase in clock rate would explain), which may be caused by the higher-performance memory subsystem of the MT6795 and/or the increased number of floating point registers available in AArch64 mode.

The MT6795 is clearly slower than its 32-bit predecessor MT6595 (which uses high-performance Cortex-A17 and Cortex-A7 cores in a big.LITTLE configuration) in most metrics, with only the heavy weighting and large performance gain for the AES and SHA1 cryptography tests  (due to the new ARMv8 instruction set) shifting the advantage for the overall score towards the MT6795.

When making a comparison with a median entry for the high performance Exynos 5433 (Exynos 7 Octa) inside the Samsung Galaxy Note 4, the MT6795 fairly consistently shows clearly lower single-core performance but higher multi-core performance.

MT6795 likely to be most cost-effective performance segment processor on the market

The exclusive use of Cortex-A53 CPU cores, and not the much more expensive and die-space consuming Cortex-A57 (or, in a 32-bit comparison, Cortex-A15/A17 cores), has positive implications for the cost of the chip. Die space dedicated to the CPU cores will be relatively low, although L2 caches will take considerable space when configured with a size that matches the desired performance level and market segment. Overall, the chip is likely to be attractive in terms of performance/dollar for the performance segment.

In terms of SoC optimizations, the chip would probably work better with the employment of additional ARM IP such as a Mali T760 or Mali-T800 series GPU, which offers advantages in combination with ARM cores such as Cortex-A53 in tandem with techniques such as AFBC, smart composition and transaction elimination, and new interconnect buses within the chip. SoCs like the MT6752 probably benefit from these optimizations, while the MT6795 cannot do so fully because of the non-ARM GPU. It seems likely that the MT6795 will be superseeded in next generation products to be announced by MediaTek in the future by a similar SoC with an ARM Mali-T760 or T800 series GPU.

Update (2 March): Based on a closed-door presentation event at the MWC, MediaTek appears to have rebranded MT6795 as Helio X10 with future Helio P series products also being announced.

Sources: MediaTek (MT6795 announcement), Geekbench browser

Qualcomm has announced new SoCs, uses new Cortex-A72 core

Recently, Qualcomm announced a number of new SoCs for the cost-sensitive and performance segments of the smartphone market, namely Snapdragon 415 and Snapdragon 425 in the 400 series, and Snapdragon 620 and Snapdragon 618 in the 600 series.

New Snapdragon 415 an 425 offer mid-range performance features

Qualcomm's product line has been somewhat inconsistent recently, with products from a series for a certain segment actually being used for a different segment. For example, although the Snapdragon 410 SoC is the mid-range 400 series, it has actually been deployed in significant numbers of cost-sensitive entry-level 4G segment devices.

There used to be a gap in Qualcomm's product line, large in terms of performance level, between the lower mid-range Snapdragon 400 and the premium level Snapdragon 801. Not too long ago, Qualcomm addressed this gap with the mid-range Snapdragon 615, featuring a total of eight Cortex-A53 cores, four with maximum frequencies in the 1.5 - 1.7 GHz frequency range and four clocked lower (e.g. 1 GHz) for lower consumption. With the new Snapdragon 415, Qualcomm is bringing a SoC similar to Snapdragon 615 to the cost-sensitive mid-range segment, largely replacing the Snapdragon 410 for that tier (as I have discussed previously, Snapdragon 410's performance is flawed in several ways).

Snapdragon 415 could be a rebranding of 615 to replace 410, or maybe not

In fact, there is a possibility that Snapdragon 415 is actually the same chip and in fact a rebranding of the same product. Both Snapdragon 415 and Snapdragon 615 have a roughly similar CPU set-up (eight Cortex-A53 cores), an identical GPU (Adreno 405) and a Cat 4 LTE modem. Although Qualcomm in its press release mentions commercial availability in end-user devices for new chips will happen the second half of the year,  if it is the same chip it is likely that Snapdragon 415 will appear earlier (since it has essentially already in production for some time as Snapdragon 615), replacing Snapdragon 410. However, in its specifications page for Snapdragon 415, Qualcomm does not mention any distinction in CPU speed between cores, making it likely that it can run all cores at the maximum clock frequency, similar to MediaTek chips already on the market.

Meanwhile, Snapdragon 425 has a CPU configuration similar to Snapdragon 415 with a higher maximum clock speed, and also the same GPU, but has a more advanced modem with Cat 7 LTE, and better ISP functionality for camera processing. A comparison can be made with MediaTek's MT6752 which also has a 1.7 GHz octa-core Cortex-A53 CPU (Snapdragon 425 probably also drops the pseudo-big.LITTLE design of Snapdragon 615). Given the clock speeds, it is likely that Snapdragon 425 is manufactured on a higher performance process than TSMC's 28LP, most likely TSMC's 28HPM, like MediaTek's chips.

Symmetric octa-core CPU configuration has advantages for multi-threaded applications

Although "LITTLE" cores in a big.LITTLE configuration can be taken advantage of in multi-threaded algorithms, most applications and algorithms are designed for and work best with processor cores running at a comparable speed, distributing the workload evenly between cores, favouring symmetric CPU configurations in which every core can run at the same maximum frequency. This shows in the very high multi-core benchmark scores of chips using such a configuration, such as MT6752. It looks like Qualcomm is quickly moving towards such as symmetrical octa-core configuration (pioneered by MediaTek, which already has comparable chips on the market) for the cost-sensitive part of the market, up to the mid-range segment.

Snapdragon 415 and 425 not likely to be cheap in terms of manufacturing cost

Although the eight Cortex-A53 cores are relatively small so their consumption of die space is relatively limited, as I discussed earlier the Adreno 405 GPU, with its medium-level performance, appears to have characteristics of a GPU targeted at higher-end segments (in terms of ALU/shader performance, for example) and is likely have a relatively large die size in relation to the cost-sensitive segments it is addressing. Because of that, Snapdragon 415 seems to be somewhat of a stop-gap measure to replace the successful, but flawed in terms of performance, Snapdragon 410 SoC, as the gross margin on this chip could be relatively small.

The proliferation of chips such as Snapdragon 415 likely to continue Qualcomm's heavy reliance on TSMC's 28LP process, which is lower-performance process technology than 28HPM. Why Qualcomm would place such emphasis on this process for smartphone SoCs is unclear, since the advantages of the 28/20HPM process are very desirable for smartphone SoCs for everything but the entry-level segment, and competitor MediaTek has adopted this process for most of its range. Qualcomm has been using 28HPM and 20HPM for its Snapdragon 801, 805 and 810, although the it is likely Snapdragon 425, 618 and 620 will also be using it.

Little heard from quad-core Cortex-A53 Snapdragon 610

It would have made sense if the Snapdragon 610 (announced as quad-core Cortex-A53 CPU and the same Adreno 405 GPU as the products discussed above) would have trickled down to the 400 series. The fact that this chip has barely appeared on the market and that it is not mentioned in the press release suggests it won't come to market at all, perhaps due to technical problems with the chip or as the result of a strategic decision. An updated quad-core Cortex-A53-based solution would certainly make sense in Qualcomm's product line.

Snapdragon 618 and 620 have premium-level characteristics

Qualcomm also announced two new performance segment processors, Snapdragon 618 and 620. These are the first announced mobile chips to feature the new Cortex-A72 processor core from ARM, which is an improved version of the high-performance Cortex-A57 processor core. Snapdragon 620 has four Cortex-A72 CPU cores clocked up to 1.8 GHz  and four Cortex-A53 cores up to 1.2 GHz in a big.LITTLE configuration, while Snapdragon 618 reduces the number of Cortex-A72 core to two to provide a better balance in terms of cost.

Although on the surface the model numbers of these new SoCs may seem close to Snapdragon 615, their specifications suggest that they are targeting a significantly higher performance segment. The memory interface is a dual-channel interface supporting LPDDR3 up to 933 MHz, clearly a defining feature for a high-end product, and making the support for QHD (2560x1600) displays a sensible feature. They also feature a new, "next-generation" GPU.

In short, despite their model number, Snapdragon 618 and 620 have little to do with Snapdragon 615 and should be thought of as processors in the same segment as processors from the Snapdragon 800 series such as as the Snapdragon 801 and Snapdragon 808. If and when Snapdragon 808 (with two Cortex-A57 cores and four Cortex-A53 cores) will appear on the market is unclear (some test results have appeared in the Geekbench database), the new announcement might suggest that it will quickly be superseeded by Snapdragon 618.

Sources: Qualcomm (SoCs announcement)

Updated February 26, 2015 (Edited and expanded to reflected likelyhood that Snapdragon 415 and 425 use a symmetrical CPU configuration, not pseudo-big.LITTLE like in Snapdragon 615).

New mobile SoCs announced at CES

At the Consumer Electronics Show in Las Vegas, USA this week, a large number of new devices as well as chips for various kinds of multimedia devices is being announced, including mobile SoCs for smartphones and tablets. Several of the newly announced SoCs use Cortex-A53 CPU cores.

Rockchip announces octa-core Cortex-A53 tablet SoC

Rockchip announced the RK3368 at the show, which is a tablet processor with eight Cortex-A53 cores clocked up to 1.5 GHz and an unnamed GPU supported OpenGL 3.1. Rockchip also claims 4Kx2K H.264/H.265 video playback capability and HDMI 2.0 display output supporting 4Kx2K resolution. Early information about this chip became available a few months ago, when it was codenamed "MayBach". Rockchip mentions support for Android Lollipop in its materials.

The quoted maximum clock speed of 1.5 GHz is not very high, but an up-to-date revision of the Cortex-A53 core should provide good CPU performance at that speed even for single-core, and the octa-core configuration will provide very good multi-core performance. At which foundry it is being produced in unclear; in the past Rockchip has been using the 28 nm SLP process at GlobalFoundries for its high-performance chips, although plans for chips produced at TSMC have been reported.

Most of the specifications suggest that the chip is targeted at the performance segment, more or less as a replacement for the RK3288 that is more suitable for tablets due to lower power consumption. Based on the fact that DirectX support up to 9.3 is claimed as well as OpenGL 3.1, the GPU is most likely a Mali-T760 GPU. The RK3288 already contains a performance-oriented Mali GPU, of which the exact nature is unclear. The memory interface is likely to be 32-bit dual-channel with support for LPDDR3, similar to the RK3288 and suitable for performance-oriented devices.

Allwinner announces low-cost quad-core Cortex-A53 tablet SoC

Meanwhile, Allwinner, Rockchip's archrival in the Chinese tablet processor market, announced the A64, a new low-cost tablet processor with four Cortex-A53 CPU cores. Allwinner quotes a price of $5 for the chip. The SoC appears to be the logical successor to the recently introduced A33 with Cortex-A7 cores, which is also a low-cost quad-core tablet processor that appears to have been less successful than anticipated. Allwinner also recently introduced an octa-core Cortex-A7-based SoC, the A83T.

The new SoC supports H.265/H.264 decoding in hardware, and is compatible with various types of DDR memory (presumably in a single channel 32-bit configuration). 4K HDMI output is also listed.

MediaTek announces Android TV and wearable device SoC platforms

Outside of the mobile space, MediaTek (which has long being prominent in the digital television SoC space, both through its internal division and through MStar, which it acquired not too long ago), announced a new digital television SoC, MT5595, with support for Android TV.  Sony will be using the chip in new LCD TV models. The chip has a big.LITTLE-type CPU configuration with two Cortex-A17 cores and two Cortex-A7 cores, and has hardware support for HVEC (H.265) and VP9 for 4K2K content streaming at 60 frames per second. As shown by the MT6595 smartphone SoC, MediaTek's Cortex-A17 implementation can provide very high single-core CPU performance, which is probably helpful in providing good performance and response times on the Android TV platform.

MediaTek has also announced an optimized solution for wearable devices based on Google’s Android Wear software. The MT2601 is equipped with a dual-core Cortex-A7 CPU up to 1.2 GHz and a single-core Mali-400 MP GPU, with support for display resolutions up to qHD (960x540). In several respects, these specifications match those of MediaTek's existing low-cost MT6572 smartphone SoC. MediaTek is touting the small die size and power efficiency of the new chip. It can be paired with various external wireless connectivity chips including the recently introduced MT6630 for Bluetooth (MT6630 also integrates advanced WiFi, GPS and FM radio functionality).

Sources: CNX Software (Rockchip RK3368), CNX Software (Allwinner A64), MediaTek (MT5595 announcement), MediaTek (MT2601 announcement)

No more wafer capacity shortage at TSMC?

For November 2014, TSMC somewhat unexpectedly reported a revenue decline to US$2.31 billion, 10% lower than the historical high achieved in October 2014, reversing several months of continually increasing monthly revenues at TSMC amid a shortage of capacity for clients of TSMC and continuous investments into capacity expansion.

An article in the Taipei Times from 14 December 2014 further reports on TSMC's sales in Q4 2014 and its future prospects, with a senior TSMC official saying that the decline was not a suprise, as "cautious inventory adjustment actions taken by some of our customers will bring slower fourth-quarter demand". There have been reports that some clients may have double-ordered chips in the face of the capacity shortage that existed previously. TSMC's sales in Q4 2014 will still be a quarterly record based on strong demand for 4G smartphones in China and increased demand for TSMC's advanced 20nm process technology.

TSMC's Q4 2014 revenues are still projected to be near NT$220 million (about US$7.0 billion), a sequential increase of about 5% from the previous quarter, which would complete a strong 27% increase in revenues for the whole year 2014 over the previous year, extending TSMC's leadership of the foundry industry.

TSMC's revenues for 2015 are forecast to further increase by 15 to 20%, based on strong demand for 20nm chips, new chips manufactured using its 16nm FinFET process technology and continuing demand for 28nm chips, as well as demand for trailing-edge 8" wafer capacity.

Apple ramp has peaked, Android chip vendors cautious

As mentioned in the recent articles, a likely major reason for the revenue decline in November and for Q4 2014 is that Apple's production of the Apple A8 and Apple A8X processors already peaked in October in order to achieve sufficient production in time for the 2014 holiday season. Additionally, demand from Android device vendors (such as Qualcomm and MediaTek) has not picked up, so that another sales decline for December 2014 is expected.

The decline in demand appears to be concentrated in the 20nm and 28nm HPM (High-Performance Mobile) process technologies, which were earlier in extremely short supply, and are used by Apple for its A8 SoCs at 20nm, and primarily at 28nm by Qualcomm for its high-end SoCs such as the Snapdragon 800 series and by MediaTek for various mid-range chips (such as MT6592, MT6595 and MT8135V), as well as its new 64-bit SoCs (MT6732, MT6752 and MT6795) that are currently ramping.

Decreased use of TSMC-produced chips by Samsung

An important contributor to the decline in demand for mobile processor capacity at TSMC is likely to be a decline in the utilization of TSMC-produced smartphone SoCs at Samsung. Samsung has recently been facing an overall sales decrease for its smartphone business, although Q4 2014 has been projected to see a recovery. However, Samsung is aggressively increasing the use of its own Exynos series SoCs in its smartphones, especially high-end models, after reduced orders from Apple left Samsung's advanced logic fabs underutilized.

Chips like the Exynos 7 Octa perform adequately for a high-end device and have significantly decreased Samsung's reliance on Qualcomm, which manufactures at TSMC. While Qualcomm is likely to continue to sell a large number of low-cost chips such as Snapdragon 410 to Samsung, the overall product mix from Qualcomm into Samsung has likely shifted to lower-end chips that have a significantly smaller die size, and thus require significantly less wafer capacity for a given amount of chips.

Transition to smaller die size for Qualcomm's mid-range performance-oriented SoCs

For some time, Qualcomm has had a gap in its product line, with Snapdragon 400 being used for the low-end as well as part of the mid-range segment, and a large performance and cost gap to the high-end Snapdragon 800 series, while Snapdragon 600 (without integrated baseband) was out of the picture. This resulted in a relatively large amount of high-end, large die-size Snapdagon 800 series chips being used in smartphones, even for models that do not quite require that level of performance.

However, Qualcomm has introduced new SoCs such as Snapdragon 615, an octa-core Cortex-A53-based SoC with a mid-range GPU, which can address the perfomance requirements of a significant part of the performance-oriented segment at a much lower cost, importantly while consuming significantly less wafer capacity at TSMC due the smaller die size of the SoC. This product transition at Qualcomm likely contributes to lower wafer requirements for Qualcomm at TSMC as production of smaller chips like Snapdragon 210, Snapdragon 410 and Snapdragon 615 increases at the expense of Snapdragon 801/805, and as a result contributes to TSMC's revenue decline.

Product transition at MediaTek

Meanwhile, MediaTek is also in a product transition from its 3G product line to its new product line with integrated 4G baseband. Because it has been late with integrated 4G, MediaTek has come under some pressure in China, with more of its sales being concentrated at the low of the market with SoCs such as dual-core chips for worldwide export markets, which take a smaller amount of wafer capacity.

MediaTek's new mid-range performance-oriented chips such as MT6752 and MT6795 are competitive, and have the potential to reduce overall market die size requirements and improve device cost and efficiency for the performance-oriented segment. However, they, as well as the lower-end MT6732, do not address the highest-volume low-end 4G segment, which in the near term is more likely to be addressed by Qualcomm with its Snapdagon 410 and upcoming Snapdragon 210 series, the latter of which implies with further reductions in wafer requirements due to smaller die size.

Other smartphone SoC clients at TSMC

HiSilicon has been producing increasing numbers of smartphone SoCs at TSMC for use in Huawei smartphones, but may have been affected by inventory issues, and there's also evidence of HiSilicon transitioning to more cost-effective designs such as the octa-core Cortex-A53-based Kirin 620, partly displacing its existing big.LITTLE Cortex-A15/Cortex-A7-based Kirin 920/925 series, which have a relatively large die size.

Other TSMC clients for leading-edge processes

Other companies that do not concentrate on smartphones such as Broadcom (embedded communications/networking) and NVIDIA (primarily PC-class GPUs, as well as high-end tablet SoCs) may welcome the increased capacity as it gives them increased production flexibility amid strong demand for their chips.

Not good for foundry competitors

Foundry competitors such as GlobalFoundries, which are already struggling, are not likely to benefit from the alleviation of capacity constraints at TSMC, because potential clients may now be less determined into moving part of their production from TSMC to alternative suppliers such as GlobalFoundries (as well as Samsung and UMC). Moving products to new foundries involves considerable investment and time since their processes are different from TSMC's processes, and as long as TSMC has enough capacity there is little reason for clients to not concentrate production at TSMC with its industry-leading performance.

Sources: DigiTimes (TSMC November revenues) , Taipei Times (TSMC article)

Updated December 26, 2014.

Another symmetric octa-core CPU-based SoC announced (HiSilicon Kirin 620)

Huawei has just announced a new SoC, Kirin 620, with an octa-core Cortex-A53 CPU. The chip is the latest in a series of newly introduced octa-core Cortex-A53-based SoCs from companies such as MediaTek and Qualcomm as well as other players.

New Kirin 620 chip appears to target cost-sensitive segment

HiSilicon shows some smart design choices with this chip. It is clearly designed to be relatively cheap to manufacture (with a relatively limited chip die area) while still providing good performance for low/mid-range devices.

In the past, HiSilicon has been using CPU cores with a relatively large die area such Cortex-A9 and Cortex-A15, which do not result in a particularly cheap or power-efficient chip. However, the Cortex-A53 is the direct successor to the very power-efficient and extremely small Cortex-A7 core, which means even with eight cores the chip will still be relatively small as well as power-efficient.

The maximum CPU clock speed of 1.2 GHz is significantly lower than most other announced Cortex-A53-based SoCs, illustrating that the chip is intended for the cost-sensitive segment. Possibly, it is manufactured on TSMC's relatively economical 28LP process technology, which limits maximum performance.

Compared to MediaTek’s and Qualcomm’s new octa-core Cortex-A53-based chips, the Mali-450 MP4 GPU is notable because it does not support the OpenGL ES 3.0 API. However, OpenGL ES 2.0 is still the standard in the mobile market, and HiSilicon can probably improve cost and performance this way (especially since Mali-T62x and Mali-T760 are not cheap in terms of die size). Mali-T760 would have been faster and more power-efficient, but Mali-450 MP4 saves cost while still providing reasonable performance.

The new chip has several similarities with MediaTek’s MT6592, which is almost a year old, and has eight Cortex-A7 cores instead of Cortex-A53 and also a Mali-450 MP4 GPU.

Octa-core Cortex-A53 core CPU provides benefits for performance/Watt and performance/dollar

Because the Cortex-A53 (like its predecessor, the Cortex-A7) has a very small die size in comparison to higher-performance cores like Cortex-A57 and Cortex-A15, the use of eight cores instead of four does not very significantly raise the cost of the chip, while greatly increasing multi-core performance. Although not quite true for HiSilicon's chip due to the relatively low clock speed, several other Cortex-A53-based chips are also clocked at a relatively high frequency (in excess of 2 GHz for MT6795), resulting in respectable single-core performance as well, and making such a configuration suitable for the performance segment.

An octa-core configuration can provide real benefits in practice in a multi-threaded OS such as Android. Applications that can readily take advantage of eight cores include the Chrome browser and software video decoding and encoding libraries, all of which can improve the user experience. Because the eight cores are usually physically split into two clusters with a separate L2 cache, there is also room for further optimizations by the kernel scheduler in order to maximize performance and power efficiency.

For example, it might be possible for the scheduler to disable one of the two clusters of four CPU cores and its associated L2 cache during normal operation (when the load is not high), resulting in low power consumption. When more CPU power is needed, the second cluster comes online. Even when there are only a few threads, the scheduler might be able to detect the need for more L2 cache memory in a particular workload and move one or more threads to the second cluster. MediaTek's CorePilot technology, with which it has had experience since the MT6592, probably involves heuristics of this kind.

Overview of symmetric octa-core Cortex-A7 and Cortex-A53-based SoCs

The following table shows an overview of currently announced octa-core Cortex-A7 and Cortex-A53-based SoCs, starting with MediaTek's MT6592 which has been available for about a year.

(Click to enlarge)

Note that Qualcomm's Snapdragon 615 is not really a symmetric octa-core because it uses a pseudo-big.LITTLE configuration with four Cortex-A53 cores clocked higher and four cores clocked lower.

Performance comparison of octa-core Cortex-A7 and Cortex-A53-based SoCs

The following tables show CPU performance (using a representative Geekbench subtest result) as well GPU performance based on GFXBench for relevant SoCs and devices for which benchmark data is available. It includes both octa-core Cortex-A7 and Cortex-A53-based SoCs, as well as other existing SoCs from different market segments, for reference.

(Click to enlarge)

The first few columns of the table show a description of the SoC with CPU configuration, the name of a representative device model using the SoC and the maximum CPU clock speed. Then comes the Geekbench JPEG Compression benchmark test, both single-core and multi-core. This Geekbench subtest has been found to be relatively sensitive to CPU performance without being very sensitive to other factors such as L2 cache size.

The rightmost columns show information about the GPU. First listed are the GPU type and off-screen performance for the GFXBench T-Rex (OpenGL ES 2.0) and Manhattan (OpenGL ES 3.0) benchmarks. The offscreen tests always render into a 1920x1080 off-screen buffer, making results comparable between devices with different screen resolutions. The actual resolution used on the device comes next, followed by on-screen T-Rex benchmark benchmark performance and information relevant for battery life and long-term performance (which is affected by thermal throttling). This includes average long-term performance of the T-Rex on-screen benchmark, the battery size of the device and the battery life in minutes when running T-Rex on-screen long-term.

Mali-T760 appears to be highly efficient

Notable is that GPU performance of the MT6752 with Mali-T760 MP2 GPU as represented by the Lenovo A70-A entry in the GFXBench database is comparable with the Snapdragon 615-based HTC Desire 820, despite the latter's higher low-level pixel processing performance (such as evident in the ALU and Alpha Blending scores) provided by the Adreno 405 GPU.

This strongly suggests that ARM has made a big leap in terms of performance efficiency with the Mali-T760 GPU core in conjunction with compression-based bandwidth optimization technologies such as ARM Framebuffer Compression, Transaction Elimination and Smart Composition as well as good integration with the Cortex-A53 CPU architecture (which already shows memory performance improvements).

Based on GFXBench power efficiency data, none of the listed SoCs appears to be particularly power-efficient with a full GPU load with the complex T-Rex benchmark, but data for the Mali-T760 MP2-based MT6752 has yet to come in. However, the best battery life entries in the GFXBench database for the Samsung Galaxy Note 4 with Mali-T760 MP6-based Exynos 7 Octa shows the ability to run the on-screen T-Rex benchmark for more than 300 minutes with reasonable sustained performance on the very high resolution screen of the Note 4, which is compatible with relatively high power efficiency of the Mali-T760 GPU.

Note that power efficiency is likely to be better for typical GPU applications that are less demanding than GFXBench's T-Rex benchmark (this affects lower-end SoCs/GPUs more than higher-end ones).

Sources: CNXSoftware (Kirin 620 announcement), GFXBench results database, Geekbench browser

Updated December 25, 2014 (Correct memory interface information for Snapdragon 615).

Analysis of GPU performance of mobile SoCs based on GFXBench results

In this post, I am analysing the GPU performance of different GPUs and SoCs based on the results database of GFXBench, one of the leading mobile GPU benchmarks. Apart from providing a GPU performance comparison for different SoCs, GFXBench results provide sufficient detail to get an impression of metrics like fill rate, triangle rate and shader performance, allowing one to draw conclusions about what the bottleneck is in a particular implementation.

GFXBench results table for mobile SoCs

The folowing table show detailed GFXBench 3.0 results for a large number of mobile SoC platforms and devices. The results are grouped by smartphone and tablet devices, and further grouped for similar chips (smartphone table) or in alphabetical order by chip (tablet table).

For a high-resolution version, view/copy/save the image above using the browser.

The same table is shown below, but sorted on the T-Rex Offscreen benchmark score in descending order, which provides a reasonable device-independent indication of GPU performance.

For a high-resolution version, view/copy/save the image above using the browser.

Top-performing SoCs: Apple A8/A8X, Snapdragon 805, NVIDIA Tegra K1 and Exynos 7 Octa

Apple's A8 and A8X SoCs, NVIDIA's Tegra K1 (both the Cortex-A15/A7-based version as well as the NVIDIA Denver-based version) as well as Qualcomm's Snapdragon 805 lead the pack for mobile GPU performance. What most of these chips have in common is a large number of GPU pixel processing cores and a wide DRAM interface (especially in the case of the Apple A8X and Snapdragon 805) to achieve high memory bandwidth. The Apple A8X has been reported by AnandTech to contain an eight cluster PowerVR Series 6 GPU, twice the number of clusters of the GPU inside the Apple A8.

In the OpenGL ES 2.0-based T-Rex offscreen benchmark, the Apple A8X as used in the iPad Air 2 leads, closely followed by the respective versions of Tegra K1 in the HTC Nexus 9 and the NVIDIA Shield Tablet. The Apple A8 and Snapdragon 805 show significantly slower but comparable performance in the T-Rex offscreen benchmark (although still very fast for most purposes), although Snapdragon 805 shows significantly higher low-level metrics such as fillrate, alpha blending bandwidth and shader processing throughput. Snapdragon 805 (with Adreno 420 GPU) has an effective 128-bit memory interface (similar to Apple A8X), which suggests the Apple A8 (with 64-bit memory interface) has greater efficiency within the limitations of the lower memory bandwidth, probably helped by the use of large on-chip caches (including the L3 cache). Samsung's Exynos 7 Octa (Exynos 5433, with Mali-T760 MP6) is somewhat slower than Apple A8 and Snapdragon 805, and so is the slowest of the high-performance processors in terms of GPU power (while being near the lead in terms of CPU performance).

In the OpenGL ES 3.0-based Manhattan benchmark (offscreen, so that the results are largely independent of screen resolution), the Apple A8X and NVIDIA Tegra K1 provide comparable performance (a score just above 2000), while the Snapdragon 805 follows at a considerable distance with a score of about 1200, similar to the score achieved by the Apple A8 inside the iPhone 6 and iPhone 6 Plus. Samsung's Mali-T760 MP6-based Exynos 7 Octa (as represented by the Exynos-based version of the Galaxy Note 4) follows with a score of about 1100.

High-end: Snapdragon 801, Exynos 5 Octa, Apple A7

Qualcomm's Snapdragon 801 with Adreno 330 GPU has been widely used in performance-oriented devices for some time and provides relatively high performance for the segment. Part of the reason for the wide adoption of the high-powered Snapdragon 801 is that Qualcomm has not had a convenient SoC offering intermediate between the Snapdragon 801 and Snapdragon 400 (between which exists a large performance and cost gap), and through its control over the high-performance smartphone market through its patent royalty leverage has been able to convince customers to use the Snapdragon 801 in a wide range of devices (as it did previously with the Snapdragon 800), with the SoC providing more performance than really necessary in many cases.

In the OpenGL ES 2.0-based T-Rex (offscreen) test, Snapdragon 801 scores approximately the same as Apple's previous generation Apple A7 SoC. Samsung's recent Exynos 5 Octa (Exynos 5430, with Mali-T628 MP6) used in the Galaxy Alpha also score about the same. The results for the OpenGL ES 3.0-based Manhattan benchmark are also comparable for these three SoCs.

PowerVR's Rogue Han (G6200) GPU with two clusters inside MediaTek's recent MT6595 does not match the performance of the other high-end chips mentioned above, although still providing perfomance clearly above current and upcoming mid-range solutions. This GPU is also implemented in Allwinner's A80 chip, which shows somewhat lower scores in a benchmark entry for an A80 OptimusBoard development board.

Cost-sensitive SoCs: Snapdragon 410 vs Snapdragon 400 vs MT6582

Rather than showing an evolutionary improvement in GPU performance, the quad-core Cortex-A53-based Snapdragon 410's Adreno 306 GPU actually shows 10% to 20% lower GPU performance than the Adreno 305 in Snapdragon 400 based on metrics like fillrate and the offscreen T-Rex benchmark. This provides evidence that Snapdragon 410 is also a cost-reduction effort in comparison with Snapdragon 400, with a smaller die size for the GPU to reduce cost. This also helps to explain why Qualcomm has aggressively pitched the Snapdragon 410 for low-end 4G smartphones as well as somewhat higher segments, with Snapdragon 410 reported to be Qualcomm's current main volume driver.

When looking at previous generation chips, the Adreno 305 in Snapdragon 400 scores higher than MediaTek's MT6582 in the offscreen T-Rex benchmark (approximately 40% better), while some low-level metrics are slower than MT6582. For example, GFXBench's Driver Overhead score is relatively low for both Snapdragon 400 and Snapdragon 410, reflecting mediocre performance when rendering lots of small objects. The fillrate benchmark is also a little lower than MT6582. The higher T-Rex benchmark performance is probably due to a more optimized and larger cache memory subsystems used in Snapdragon 400 and 410. Exactly how Snapdragon 400/410 compares with the MT6582 and other solutions in other benchmarks and games is beyond the scope of this article.

The next generation of efficient Cortex-A53-based mid-range SoCs: Snapdragon 610 and 615, MT6732 and MT6752

Several new chips for the mid-range performance segment are emerging that use a quad or octa-core Cortex-A53 CPU configuration. The use of Cortex-A53 cores at a relatively high clock frequency is promising to significantly improve power efficiency and cost for this segment (which might previously have required the use of more costly SoCs such as Snapdragon 801). This CPU configuration provides adequate single-core performance and (in the case of an octa-core CPU) great multi-core performance.

Both Qualcomm and MediaTek have introduced SoCs in this class, which also introduce new GPU architectures. Qualcomm's Snapdragon 610 (quad-core Cortex-A53) and Snapdragon 615 (octa-core Cortex-A53) utilize the new Adreno 405 GPU, while MediaTek's quad-core MT6732 and octa-core MT6752 utilize a Mali-T760 MP2 GPU (Mali-T760 has also been adopted by Samsung and others).

T-Rex offscreen performance of Snapdragon 615's Adreno 405 GPU (as represented by an entry for a Lenovo device) with a score of about 850 clearly puts the chip in the performance-oriented segment, since Snapdragon 400 and 410 score not much more than 300 in this benchmark. The OpenGL ES 3.0 Manhattan offscreen benchmark score is similarly significantly higher (about three times higher than Snapdragon 400/410). Low-level metrics are all fairly high for a mid-range device, with only fillrate being limited by the 32-bit DRAM interface.

MediaTek's MT6752 with Mali-T760 MP2 (as represented by a Gionee device entry) shows scores for T-Rex and Manhattan that are comparable with Snapdragon 615. Raw low-level metrics such as ALU, Alpha Blending and fillrate are clearly lower than Snapdragon 615, with only Driver Overhead being superior, suggesting that new ARM optimization technologies such as ARM Framebuffer Compression, Smart Composition Transaction Elimination are already having a positive effect on real-world performance, especially within the bounds of a 32-bit DRAM interface, keeping device cost down.

In terms of cost, the ability of MediaTek's MT6752 to provide good performance for a mid-range device, comparable to Snapdagon 615, with an economical 32-bit DRAM interface, make the chip look very attractive. This also provides evidence that ARM has made somewhat of a breakthrough in terms of performance efficiency with Mali-T760 and the associated optimization techniques mentioned above, mostly based on compression techniques, which will revolutionize performance for economical devices with a 32-bit memory interface that have limited memory bandwidth.

MediaTek's quad-core MT6732 (as represented by an Asus device entry), which also has a Mali-T760 MP2 GPU (but clocked lower than in the MT6752) scores lower but still very respectable (especially for the real-world T-Rex and Manhattan benchmarks) for a mid-range device. There have been reports though suggesting that the Mali-T760's efficiency benefits come at the cost of a relatively large chip die size for a cost-sensitive device, so that a chip such as the MT6732 is not suitable for the high-volume entry-level 4G market (for which Snapdragon 410 is likely to be much more suitable). MediaTek is addressing this with its upcoming MT6735 with cheaper Mali-T720 GPU, which does not appear to offer the bandwidth optimization techniques of the Mali-T760.

MT6592 still has competitive GPU performance

MediaTek's octa-core MT6592 smartphone chip (which was released almost a year ago) with a T-Rex offscreen score in excess of 700 has GPU performance that roughly matches that of the upcoming mid-range chips described above, which are addressing approximately the same segment. The high GPU clock speed of the Mali-450 MP4 GPU probably drives the high scores.

The disadvantages of the MT6592 are a lack of OpenGL ES 3.x support and a likely greater memory bandwidth bottleneck when running at high screen resolutions such as 1920x1080, which also impacts power efficiency. GFXBench's battery life benchmarks when running T-Rex long-term are mediocre for most MT6592-based devices, including devices using a 1280x720 resolution, although it is likely that less demanding 3D applications exhibit better battery life. The Cortex-A7 CPU cores (typically clocked at 1.7 GHz) are also slower than the eight Cortex-A53 cores inside a chip like the MT6752 (but still provide plenty of performance).

RK3288's Mali-T764 GPU: Exact nature unclear

Rockchip's RK3288 is a relatively high performance SoC intended primarily for tablets but currently mainly implemented in devices such as media boxes and development boards. For a long time, Rockchip has advertised its RK3288 SoC as featuring an ARM Mali-T764 GPU. This is confusing because ARM has never announced a GPU with that name. ARM's Mali-T760, also used in new SoCs from other companies such as Exynos 5433 (Exynos 7 Octa) and several new MediaTek SoCs, comes close, and one could assume Rockchip means a Mali-T760 MP4 configuration.

However, in the GFXBench results database, all device entries (mainly representing Android TV box devices, but also including tablets such as the Teclast P90HD) for the RK3288 show a set of GL_EXTENSIONS that is identical to that of devices with a Mali-T628 or Mali-T624 GPU. In particular, the GL_EXT_disjoint_timer_query, GL_EXT_sRGB and GL_EXT_sRGB_write_control extensions, which seem to be associated with Mali-T760-class devices, are missing. Whether this means that the RK3288 actually does not contain a Mali-T760-class GPU but instead an older generation Mali-T62x GPU, or this simply reflects non-optimal drivers, is unclear, but there certainly is a suggestion that the GPU inside the RK3288 is actually of an older (Mali-T62x generation) type.

Earlier, Rockchip was not exactly forthcoming about the exact CPU cores inside the RK3288, which have been proven to be Cortex-A12 instead of Cortex-A17, even though ARM later helped Rockchip by declaring that Cortex-A12 will be also referred to as Cortex-A17 (even though it is technically a different core for which Rockchip was one of the few known customers), and CPU performance from benchmarks such as Geekbench suggests the version of the Cortex-A12 core inside the RK3288 does not quite perform as fast as a real Cortex-A17, clock-for-clock.

While RK3288 does support OpenGL ES 3.0 (as do both Mali-T62x and Mali-T760), GFXBench does not allow the OpenGL ES 3.0 Manhattan benchmark to run on this chip for several TV box devices, which one would normally expect to be possible even if the GPU is technically Mali-T62x class. However, the Teclast P90HD tablet entry does show Manhattan benchmark results, which are consistent with a Mali-T62x MP4 GPU (or perhaps Mali-T7xx) configuration, while also showing reasonable sustained GPU performance and power efficiency.

Other tablet solutions

MediaTek's MT8382 chip for 3G tablets shows performance similar to that of the MT6582 smartphone chip, as expected, with a T-Rex offscreen score of about 220. MediaTek's previous generation WiFi-only MT8125 with PowerVR 544MP shows limited performance, lower than Mali-400 MP2 based designs, and slightly less than its previous-generation MT6589T smartphone chip with a similar GPU.

MediaTek's WiFi-only MT8127 with Mali-450 MP4 for somewhat higher performing tablets, shows higher performance with a T-Rex offscreen score of about 500, higher than the typical score of 350 of the popular RK3188T with Mali-400 MP4, which has commonly been used in tablets. However, the performance of the Mali-450 MP4 GPU appears to be clearly lower than the similar GPU configuration in the octa-core MT6592 smartphone chip, which scores more than 700 in T-Rex offscreen and scores higher in low-level metrics such as fillrate, probably due to the lower GPU clock speed of the MT8127. The MT8135V used in recent Amazon Kindle Fire tablets shows good mid-range performance with a T-Rex offscreen score of 740. This results in good performance given the low screen resolution of the Kindle tablets, but performance is otherwise low for a PowerVR Rogue class GPU.

As mentioned, Rockchip's popular RK3188T chip with Mali-400 MP4 clocked at about 400 MHz scores about 350 in T-Rex offscreen, which is a higher than typical cost-sensitive tablet processors, and also scores higher in low-level metrics such as fillrate.

Thanks to the PowerVR 544 MP2 GPU, Allwinner's aging A31s processor still shows higher performance than Mali-400 MP2-based chips such as MT8382. Allwinner's more recent mass-market chips such as A23 and A33 with Mali-400 MP2 have been slow to come to market, and I haven't yet analyzed their GPU performance, but it is unlikely to be spectacular.

An entry for Leadcore's L1860 with Mali-T628 MP2 GPU shows a T-Rex offscreen score of about 580, and it is compatible with OpenGL ES 3.0. The score reflects a fillrate that might still allow higher resolutions such as 1920x1080 to be used in tablets using this chip, with reasonable but not great GPU performance to be expected, helped by a relatively high GPU clock speed.

Intel' s Atom Z3745 processor for the tablet market shows high performance for its class, with the Acer A1-840 FHD (which uses the higher-end Z3745F variant with 64-bit memory interface) scoring a fairly impressive 1181 in the T-Rex offscreen benchmark. The more commonly used cost-sensitive Z3745G with 32-bit memory interface, as used in the Acer A1-840, scores a still very reasonable 853 in T-Rex offscreen. Both processors have relatively good OpenGL ES 3.0 performance, resulting in relatively high Manhattan benchmark scores for their class (higher than chips such as Snapdragon 610/615).

Finally, the results for the Actions ATM7021, a fairly recent ultra-low-end tablet processor, shows signs of blatant benchmark cheating, with the offscreen (1920x1080) T-Rex score being several times higher than the on-screen score for a device with a screen resolution of 1024x768 (one would expect the offscreen score to be several times lower).

Note about T-Rex benchmark and cost-sensitive GPUs

Because GFXBench's T-Rex benchmark targets a fairly detailed and advanced level of rendering that requires a reasonably high-end GPU for good results, the T-Rex benchmark is likely to understate practical GPU performance for low-end devices. Part of the reason for this is the much lower L2 cache associated with low-end GPU like Mali-400 MP2 and especially Mali-400 MP, which is not likely to be enough to satisfy the T-Rex benchmark's relatively large textures and other demands, resulting in much more expensive external RAM access and a relatively low benchmark score. More typical, less demanding GPU applications of the Angry Birds and Temple Run-type are likely to perform better in relative terms on these platforms (although there will still be variation between chips), and GFXBench's low-level benchmarks provide some information on this.

GFXBench's battery life benchmark is also likely to understate practical battery life for devices such as Mali-400 MP and probably Mali-450 MP because of its higher than typical rendering complexity and relatively large texture working set, with battery life for less demanding GPU applications likely to be significantly better.

Sources: GFXBench results database

Updated December 4, 2014 (Make corrections and add comments about Snapdragon 615's 64-bit memory interface vs MT6752's 32-bit memory interface), add section about T-Rex benchmark's complexity negatively affecting low-end CPU scores.
Updated December 25, 2014 (Correct Snapdragon 615 memory interface width).
Updated December 26, 2014 (Provide slightly updated, sorted GPU benchmark results tables).