Friday, November 7, 2014

Analysis of tablet processors by chip company, with a focus on Geekbench CPU performance

The Geekbench browser, which includes hundreds of thousands of mobile benchmark results, provides access to a wealth of information about the CPU and memory performance of smartphone and tablet SoCs. Because certain subtests within Geekbench results (such as the single-core JPEG Compress test) correlate well with CPU clock speed for a given CPU core, it is possible to determine the actual maximum clock speed of the CPU, which sometimes does not correspond to the advertised clock speed or even the clock speed reported by the operating system.

By assessing the number of entries for a specific chip or model, the database of also provides an indication about the unit volume and popularity of specific chips and models. The approximate arrival on the end market of specific chips can also be estimated.

In this post, I am analysing the Android ARM and x86-based tablet processor market of the last two years or so from the low-end (mostly chip used in Chinese white-box tablets) to high-end devices from well known brand names, with a focus on CPU performance and other information that can be found after studying the Geekbench results database. The article takes on tablet SoC chip companies in alphabetical order, one-by-one.

Although the article specifically focuses on tablet chips, there is some overlap with smartphone chips since many players in smartphone chip space also compete in tablets with solutions that are generally similar to their smartphone chip solutions. HiSilicon, the chip division of Huawei, is becoming more prominent for smartphone SoCs but has been omitted because it does not really target tablets. A similar argument applies to the Chinese low-end smartphone chip designer Spreadtrum. These companies may be covered in a future update or in an article focusing on smartphone chips.

Actions Semiconductor


Actions a Chinese chip company with a long prior history in the MP3 player chip market, which has operated at the bottom-level of the white-box tablet market in the last few years.

Chip      Arrival  Fab    CPU             Clock speed  Geekbench  Multi   GPU
                          configuration   (typical)    JPEG C.    core x

ATM7021   Q4 2013  40nm  2 x Cortex-A5    1.3? GHz                        PowerVR SGX540
ATM7029A  Q1 2013  40nm  4 x Cortex-A5    1.0 GHz      296   681  2.30    Vivante GC1000
ATM7029B           40nm  4 x Cortex-A5    1.2? GHz                        PowerVR SGX540
ATM7059            28nm  4 x Cortex-A9    1.6 GHz                         PowerVR SGX544 MP

The ATM7029A from Actions is a low-end quad-core SoC that was one of the first affordable quad-core tablet processors to appear on the market, and has been sold in fair numbers in low-end tablets. However, the chip cuts corners with regard to performance in a rather unorthodox way. Actions advertised the chip as containing Cortex-A9 (later "Cortex-A9 family") CPU cores, while actually containing Cortex-A5 cores that perform about half as fast at a given clock speed (also significantly slower than Cortex-A7). Actions also modified the Android kernel to hide the actual CPU core type and also to falsely report a 1.2 GHz clock speed while the actual maximum speed is 1.0 GHz. The SoC displays very poor multi-core performance scaling for a quad-core CPU of only 2.3x for the JPEG Compress test in Geekbench, probably due to a very small and slow L2 cache.

The AT7029B is an improved version of the ATM7029 that replaces the less compatible Vivante GC1000 GPU with a more proven PowerVR SGX540.

The ATM7021A is an ultra-low-end dual-core Cortex-A5 processor that arrived in the market at the end of 2013. It only supports 512MB RAM and has been sighted in ultra-cheap tablets advertised on the internet.

The ATM7039c/7039s/7059 family consists of higher performance SoC designs that incorporate a quad-core Cortex-A9 running at 1.6 GHz. The ATM7039s and ATM7059 are manufactured at 28nm so have increased power efficiency, although the aging Cortex-A9 core is much less power efficient (as well having much large die area) than the Cortex-A7 used by most competitors. The chips have been in the pipeline for some time and Actions remains hopeful that they will appear on the market in 2014. However, it terms of cost efficiency the chips give the impression of following Rockchip's RK3188(T) long after the fact at a time when such a solution has almost ceased to be competitive.

Allwinner Technology


Allwinner is a Chinese tablet chip company that for some time (2012-2013) dominated the worldwide unit volume for tablet processors with cost-effective chips like the A1x series, and has probably shipped more than 100 million units in total. More recently, the company has suffered from loss of market share due to problematic and delayed new product introductions.

Chip      Arrival  Fab    CPU              Clock speed Geekbench   Multi   GPU
                          configuration    (typical)   JPEG C.     core x

A10       Q1 2012  55nm   1x Cortex-A8     1.00 GHz     423   424  1.00    Mali-400
A13       2H 2012  55nm   1x Cortex-A8     1.00 GHz     416   418  1.00    Mali-400
A20       Q3 2013  55nm   2x Cortex-A7     1.00 GHz     384   785  1.97    Mali-400 MP2
A23       Q3 2014  40nm   2x Cortex-A7     1.20 GHz     463   922  1.99    Mali-400 MP2
A31s      2013     40nm   4x Cortex-A7     1.01 GHz     387  1571  4.06    PowerVR SGX544 MP2
A33       Q3 2014  40nm   4x Cortex-A7     1.20 GHz     466  1450* 3.11*   Mali-400 MP2
A80T      Q3 2014  28nm   4x Cortex-A15/A7 1.60 GHz     927  4020  4.34    PowerVR Series 6
A83T      Q4 2014? 28nm   8x Cortex-A7     2.0? GHz                        PowerVR
* The CPU performance of the A33 shows different CPU scaling in different entries, with some close to 4 as expected for a fully utilized quad-core CPU, while many others show a scaling factor of only about 3.1 or even as low as 2.6. Some other scores seem to correlate with the CPU scaling factor variation, with the multi-core JPEG Decompress result scaling to all CPUs when the JPEG Compress test is low. Scheduling characteristics such as thermal throttling or other factors could be involved.

The A10 was Allwinner's first successful chip targeting tablets, with its relatively high level of integration providing significant cost advantages, which catapulted Allwinner into dominance of the Chinese white-box tablet market in 2012. The A13 was a cost-reduced version of the A10 with a 16-bit external memory interface, which later caused problems as memory bandwidth requirements increased with newer Android versions and higher resolution screens. The old Cortex-A8 CPU core had relatively competitive integer performance while floating point performance was much lower than more recent designs.

The A31s (a cost-reduced version of the A31 that was released a little earlier), a quad-core Cortex-A7-based SoC with a powerful PowerVR SGX544 MP2 GPU, arrived on the market in 2013 and was more or less Allwinner's last succesful product introduction. Although the 40nm process limited clock speeds due to power and heat limitations, the A31/A31s were a reasonable success in higher-end Chinese tablets and also used by some well known brand names such as HP, although due to cost not suited for the really high-volume part of the Chinese white-box market. This chip has continued to be sold for a long time.

The dual-core A20 was intended as a pin-compatible successor to the succesful A10 processor, which was also manufactured at 55nm as early as 2012 and widely used at the time. The A20 is notable for using Cortex-A7 cores with a trailing-edge 55nm process. Originally announced in 2012, the product suffered from serious delays and quality issues related to firmware when it arrived in the market in the second half of 2013 and was not a success, contributing to Allwinner's decline. I have personal experience with an early A20-based Android tablet which came with grossly misconfigured firmware (unstable, running at 0.7 GHz, with very slow screen refresh), which nevertheless ran a custom Linux OS without problems at 1.0 GHz, suggesting that much of the problem was very sloppy software engineering related to low-level chip initialization in the Android firmware.

The A23 is the replacement for the A20 using a more sensible 40nm process. However, it also did not come to market smoothly and the Geekbench database provides evidence that it only arrived on the market as recently as Q3 2014, being more or less immediately superseeded by the Allwinner's quad-core A33 which is arriving at the same time. Geekbench results provide evidence that the kernel has been modified by Allwinner to falsely report the CPU speed as 1.54 GHz, with all shipping devices actually running at an estimated maximum speed of 1.20 GHz.

The quad-core A33 is logical extension of the A2x and was announced in June 2014 as a entry-level tablet solution, with mass production already having commenced, highly important for any recovery of Allwinner's market position. As of early November 2014, a few entries in the database have appeared suggesting the use of the A33 but this is not yet suggestive of a successful product introduction. The results listed seem to reflect devices based on A23 ("sun8i") firmware, and show lower than expected multi-core performance scaling of only about 2.6 - 3.1 for the Geekbench JPEG Compress benchmark (close to 4 would be expected), which could be due to limited L2 cache size or other factors, and the chip also shows a very low memory performance score. A possible explanation for the lower than expected performance is that the L2 cache (which should have the very reasonable size of 512KB according to Allwinner) is disabled due to hardware defects in earlier revisions of the A33. However, some recent entries in the Geekbench database show CPU scaling close to 4.0 (as expected) for A33-based devices, with variation for other benchmark tests such as JPEG Decompress also being observed. CPU clock speed appears to be falsely reported as 1.34 GHz, because actual single-core performance suggests a 1.20 GHz maximum clock speed for the Cortex-A7 cores. Allwinner has announced that HP (who earlier used the A31s) is using the A33 in the new HP 7 G2 and HP 8 G2 tablets, and mentioned having achieved one million units shipments of A33. However, the Amazon website evidence shows no reviews for these models, suggesting that actual volume availability is still doubtful. The A33 being another failed product introduction from Allwinner cannot be ruled out at this point.

Finally, the ambitious octa-core big.LITTLE A80 SoC is Allwinner's attempt to address the high-performance market. After several delays, which saw the A80 pitched mainly at development boards and other non-tablet applications, with suggestions of power and heat issues, numerous entries for the Allwinner A80T-based Onda V989 tablet have started to appear in the Geekbench database in the last few months. The results are consistent with a Cortex-A15 clock speed of about 1.6 GHz, lower than the advertised 2.0 GHz. This is confirmed by independent research. Although the chip provides high performance relative to previous Allwinner chips, performance is still lower than previous generation, lower-power SoCs such as Qualcomm's Snapdragon 800 for smartphones. The chip also shows lower multi-core performing scaling than comparable chips from competitors such as HiSilicon's Kirin 920 for smartphones, although there is evidence that the Cortex-A7 cores are also utilized (use of Global Task Switching), as well as showing low memory performance for a SoC with a dual-channel memory interface.

Intel


Intel has started targeting the tablet market in earnest only recently in 2014, using its increasingly efficient Atom processor cores and SoCs and employing a contra-revenue strategy that subsidizes tablet manufacturers that use its platform. First gaining traction in the first half of 2014 with brand-name manufacturers such as Asus, in the second half of 2014 Intel started penetrating Chinese white-box tablets primarily due to the introduction of lower cost Atom SoCs with a 32-bit memory interface such as Z3735G/Z3736G and addition to the Z3735F/Z3736F with 64-bit memory for higher performance segments, also helped by a general shortage of efficient tablet processors from competitors such as MediaTek due to the tight wafer capacity environment at TSMC. Because of the advanced 22nm process, Intel's SoCs provide relatively high CPU and GPU performance as well as high power efficiency. Part of the efficiency advantage stems from Intel's ability to integrate a fast and large 2MB L2 cache (Z37xx series), much larger than the L2 cache in typical cost-sensitive tablet processors.

Chip      Arrival  Fab    CPU              Clock speed Geekbench   Multi   GPU         Memory
                          configuration    (typical)   JPEG C.     core x              Interface

Z2560     Q2 2013  32nm   2x Saltwell      1.6 GHz      617  1711  2.77    SGX544 MP2  2 x 32-bit
Z2580     Q2 2013  32nm   2x Saltwell      1.6 GHz                         SGX544 MP2  2 x 32-bit
Z3735F    Q3 2014  22nm   4x Silvermont    1.33 GHz*    821  2803  3.35    Intel HD    64-bit
Z3735G    Q3 2014  22nm   4x Silvermont    1.33 GHz*    827  2773  3.42    Intel HD    32-bit
Z3736F    Q4 2014  22nm   4x Silvermont    1.33 GHz*    968  2858  2.95    Intel HD    64-bit
Z3736G             22nm   4x Silvermont    1.33 GHz*                       Intel HD    32-bit

* The chips have a so-called burst (turbo) frequency of 1.83 GHz (Z3735) or 2.16 GHz (Z3736).

Intel's Atom SoCs for mobile devices, although compatible with the x86 and x86-64 instruction sets used with PC processors, are based on CPU cores specifically designed for the mobile market and not derivatives of PC-class architectures.

The Saltwell core (which does not support x86-64) in previous generation Atom SoCs such as Z2560 and Z2580 has performance approximately equivalent to an ARM Cortex-A7 clocked at the same frequency, but the higher typical clock speed of 1.6 GHz results in higher single-core performance than typical Cortex-A7 configuration that are clocked lower. However, the dual-core CPU configuration with HyperThreading results in lower multi-core performance scaling than a typical quad-core Cortex-A7. The per-core 512K L2 cache is not really optimal for mobile applications and suggests that the architecture was not yet fully optimized for low power mobile applications, and overall the SoCs have significantly lower performance/Watt than competitive solutions that use ARM Cortex-A7 cores.

The current generation Z373x series are faster than Z25xx with improved power efficiency and fall somewhere in the mid-range with regard to performance, since they do not reach pure CPU processor speed of competitive mobile SoCs  targeting the performance segment (approaching the speed of less optimized Cortex-A1x designs like Allwinner A80T and RK3288, but falling short of the performance of high-end Exynos and Snapdragon 801/805 chips for tablets and smartphones).

The Silvermont-based SoCs show evidence of an optimized memory subsystem, so that the Z3735G with 32-bit memory shows memory performance comparable to Rockchip's RK3288 with a much more expensive dual-channel memory design. The CPU burst mode benefits single-core performance but means that multi-core performance does not scale as well as most ARM-based chips. The SoCs also have relatively fast GPU performance for a mobile chip, benefiting from the low power design and the large cache memory inside the chip.

Leadcore Technology


Leadcore is an upcoming Chinese designer of SoCs for smartphones that has been on focusing on the TD cellular standards primarily used in China, and also offers tablet chips with integrated modem. Although still a relatively small player, its designs show evidence of good product planning with efficient, cost-effective solutions and the company has attracted the attention of Xiaomi, which is rumoured to be interested in acquiring a majority stake in the company.

Chip      Arrival  Fab    CPU              Clock speed Geekbench   Multi   GPU            Modem
                          configuration    (typical)   JPEG C.     core x

LC1913    2013?    40nm   4x Cortex-A7     1.4 GHz                         Mali-400 MP2   3G (TD)
LC1960    2014     28nm   6x Cortex-A7     2.0? GHz                        Mali-T628 MP2  4G
LC1980    2014?                                                            Mali-T720 MP6

On paper, the LC1913 appears to be a cost-effective chip for tablets with integrated 3G connectivity, being similar to MediaTek's MT8382 but on a 40nm instead of a 28nm process. I have not yet located any entries using this chip in the Geekbench database. The hexa-core LC1960, which most likely has a dual-channel external memory interface like the LC1860 for smartphones, promises to be a reasonably balanced, efficient design that provides good but low-power CPU performance while addressing performance bottlenecks with the use of a dual-channel memory interface, potentially making it suitable for higher resolution screens (but see note below about fillrate of the Mali-T628 MP2 GPU). Although the dual-channel memory increases PCB cost, the SoC has the hallmarks of being relatively low-cost and the wide memory interface may in fact contribute to increased power efficiency because of the reduction in memory transaction duration. This is one of the first chips to combine a wide memory interface with a relatively efficient CPU configuration (most existing chips with dual-channel memory tend to be high-end designs using heavy, performance-oriented CPU cores such as Cortex-A15, Krait-400 or Cortex-A57 as well as heavy GPUs).

The Mali-T628 MP2 GPU clocked at about 690 MHz inside the L1960 provides greatly improved triangle throughput (173 Mtri/s) when compared to the Mali-400 from typical low-end SoCs, as well as OpenGL 3.x support. However, the MP2 configuration limits pixel throughput to 1380 MPix/s, equivalent to Mali-400 MP2 or 450 MP2 clocked at the same frequency. Since comparable GPUs used by competitors (such as Mali-450 MP4 used by MediaTek and HiSilicon and Mali-T628 MP4 and MP6 used by HiSilicon and Samsung) have at least double the amount of GPU cores and thus twice the pixel rate at the same clock frequency, and are already relatively limited in fill-rate when compared to high-end GPUs from competitors, it remains to be seen how much of a bottleneck this willl be in practice. Game performance is likely to be severely impacted at higher screen resolutions.

MediaTek


MediaTek is a Taiwanese company with a relatively long history of activity and success as a chip platform provider for the the Chinese mobile phone market. MediaTek also has a long history targeting segments such as digital TVs and set-top boxes, DVD players and several other segments, and has generally been successful in those segments. In the past few years, MediaTek has had a large share of the SoC market for smartphones among Chinese manufacturers and other cost-sensitive manufacturers with cost-effective, power efficient, highly integrated SoCs. MediaTek was the company that spearheaded the emergence of a multi-core ARM Cortex-A7 configuration manufactured at 28nm as a very efficient, low cost and adequately performing CPU solutions for smartphones ranging from entry-level to mid-range. Since 2013, MediaTek has also been successful in the tablet chip market, with both modemless application processors targeting WiFi-only tablets and chips with integrated modem.

Chip      Arrival  Fab    CPU              Clock speed Geekbench   Multi   GPU                Modem
                          configuration    (typical)   JPEG C.     core x

MT8125    H1 2013  28nm   4x Cortex-A7     1.20 GHz     472  1893  4.01    PowerVR SGX544 MP  -
MT8121    Q2 2014  28nm   4x Cortex-A7     1.30 GHz     505  2002  3.96    PowerVR SGX544 MP  -
MT8127    Q3 2014  28nm   4x Cortex-A7     1.30 GHz     508  2023  3.98    Mali-450 MP4       -
MT8135V   Q3 2014  28nm   2x Cortex-A15/A7 1.50 GHz     896  1884  2.10    PowerVR Series 6   -

MT8389    2H 2013  28nm   4x Cortex-A7     1.21 GHz     469  1894  4.04    PowerVR SGX544 MP  3G
MT8312    Q4 2013  28nm   2x Cortex-A7     1.30 GHz     505  1011  2.00    Mali-400 MP        3G
MT8382    Q1 2014  28nm   4x Cortex-A7     1.30 GHz     505  2013  3.99    Mali-400 MP2       3G
MT8392    2014     28nm   8x Cortex-A7     1.66 GHz     644  4745  7.79    Mali-450 MP4       3G
MT8732    Q4 2014? 28nm   4x Cortex-A53    1.5? GHz                        Mali-T760 MP2      4G
MT8752    Q4 2014? 28nm   8x Cortex-A53    1.69 GHz     952* 5046* 5.30*   Mali-T760 MP2      4G
* The CPU performance of the MT8752 as reported for the CUBE T7 and for the equivalent MT6752 for smartphones shows different CPU scaling in different entries, with some around 7.7 as expected for a fully utilized octa-core CPU, while others show a scaling factor of about 5.3. It is notable that the PNG Decompress test shows CPU scaling close to 8 when JPEG Compress scaling is 5.3, while PNG Decompress scaling is a little above 5 when JPEG Compress scaling is close to 8. This could the result of scheduling algorithm differences, or something else related to Geekbench, since similar behaviour with regard to JPEG Compress benchmark variation is also noticeable for recent entries for other chips like the Allwinner A33.

MediaTek's MT8125 was its first really successful tablet chip, providing high power efficiency and good performance. Performance and efficiency benefits from four low-power Cortex-A7 cores, a relatively large 1MB L2 cache, and a PowerVR SGX544MP GPU. The chip was prominently adopted by the Asus MemoPad 7 HD and other brand-name tablets.

The MT8121 is a lower-cost, more highly integrated version of the MT8125 that does not appear to have been widely used outside of a few Lenovo tablet models. The MT8127 is a relatively fast and cost-efficient tablet processor within the bounds of a single-channel memory interface, with the Mali-450 MP4 GPU providing relatively good game performance as long as the resolution is not too high. Both processors appear to have been affected by the shortage of wafer supply for MediaTek in mid-2014, with some production capacity most likely prioritized for the MT8135V used in new Amazon Kindle tablets, as well as higher-margin tablet processors with integrated modem.

The MT8135V is a variant of the high-end MT8135 tablet processor that was announced in mid-2013 but has failed to materially appear on the market. The MT8135V appears to be a custom design for new Amazon Kindle tablets that are positioned at the entry-level segment of the US retail market, probably as the result of a long-standing agreement. However, the MT8135V shares much of the MT8135's higher-cost design features making it seem rather unsuitable for entry-level tablets with a small form factor, although the memory interface has been halved from double to single-channel. Power efficiency is also likely to be a problem. It is ironic that use of the MT8127, although having lower single-core performance, would probably easily have fit the bill for the Kindle tablets with significant advantages for cost and power consumption.

MediaTek has been one of the first companies to offer cost-effective solutions for tablets with integrated 3G cellular data or voice connectivity, mostly based on comparable smartphone products, and has for some time dominated that market. The previous-generation MT8389(T) corresponded to the MT6589(T) for smartphones, while the dual-core MT8312 and quad-core MT8382 are the equivalent of the MT6572 and MT6582. The MT8392 matches the MT6592 octa-core smartphone processor. Tablet manufacturers also commonly utilize MediaTek's smartphone chips directly. Chip such as the MT8312/MT6572 and MT8382/MT6582 have a relatively optimized CPU achitecture, with no unexpected bottlenecks, providing good performance for their cost segment.

The upcoming MT8732 (quad-core) and MT8752 (octa-core) are Cortex-A53-based tablet SoCs with integrated 4G modem that correspond to similar upcoming chips for smartphones (MT6732 and MT6752). The use of a many-core Cortex-A53 configuration is promising to significantly raise performance for low-power SoCs and is likely to be able to address several segments including the high-performance segment, while greatly reducing cost. There are signs that the MT8732, because of the relatively large die area associated with the Mali-T760 MP2 GPU core, will not be cost-effective enough for entry-level segments and will be superseeded by a chip (equivalent to MT6735 for smartphones) that has a more economical but lower-performance Mali-T720 GPU.

NVIDIA


NVIDIA, with a long history as a leader in PC, console and laptop GPUs, has recently increased its focus on the tablet market and more or less given up on its long-term goal of penetrating the high-volume smartphone market with integrated SoCs. NVIDIA has been designing its Tegra tablet processors for tablets for quite some time, but has seen mixed success, while eventually not being successful in the high-volume mainstream tablet market. It has gained a few high-profile design wins for high-end devices, most recently for the HTC Nexus 9.

Chip              Arrival  Fab   CPU                 Clock speed  Geekbench   Multi  GPU
                                 configuration       (typical)    JPEG C.     core x
Tegra 250 T20     Q1 2010  40nm  2x Cortex-A9        1.0 GHz                         GeForce ULP
Tegra 3 T30       Q4 2011  40nm  4x + 1x Cortex-A9   1.4 GHz       605  2238  3.70   GeForce ULP
Tegra 4 T114      Q2 2013  28nm  4x + 1x Cortex-A15  1.8 GHz       938  3850  4.10   GeForce ULP
NVIDIA K1         Q1 2014  28nm  4x + 1x Cortex-A15  2.2 GHz      1296  5359  4.14   Kepler DX1
NVIDIA K1 (ARMv8) Q3 2014  28nm  2x NVIDIA Denver    2.5 GHz      2002  3941  1.97   Kepler DX1

NVIDIA's Tegra and Tegra 2 processors saw fairly widespread adoption in the early days of the tablet market. Tegra 2 had some architectural deficiencies that made it less competitive, for example, it did not have an up-to-date video decoder, and lacked ARM's almost standard NEON SIMD extension. NVIDIA was not able sustain its market share momentum as the market became increasingly dominated by Chinese white-box tablets as well as brand names such as Apple and Samsung.

NVIDIA has developed its own ARMv8-compatible CPU core, Denver, which is a large core with very high single-core performance, and which has been implemented in the ARMv8 version of the NVIDIA K1 processor in a dual-core configuration. The chip provides leading single-core performance, but multi-core performance is less than even upcoming mid-range solutions. The GPU performance of both K1 processors is industry-leading.

Rockchip


Chinese company Rockchip, which has a history as a supplier of MP3/MP4 video players, held a strong position in the very early tablet market before Allwinner displaced it with its A10 chip in 2012. Rockchip subsequently regained traction with relatively high-performing chips including the RK3066 and RK3188, and later expanded its product offering for low-end segments. Although Rockchip has led the tablet processor market in 2014 in terms of volume, it has continued to use Cortex-A9 cores for most of its products which are considerably less efficient in terms of chip cost (die area) and power efficiency when compared to the Cortex-A7 cores used by competitors.

Chip      Arrival  Fab    CPU             Clock speed  Geekbench   Multi    GPU
                          configuration   (typical)    JPEG C.     core x
RK2926/28 2013     55nm   1x Cortex-A9     1.01 GHz     430   430  1.00     Mali-400 MP
RK3066    Q3 2012  40nm   2x Cortex-A9     1.61 GHz     696  1202  1.73     Mali-400 MP4
RK3188    Q2 2013  28nm   4x Cortex-A9     1.61 GHz     699* 2604* 3.73     Mali-400 MP4
RK3188T   Q3 2013  28nm   4x Cortex-A9     1.42 GHz     617  2441  3.96     Mali-400 MP4
RK3026/28 1H 2014  40nm   2x Cortex-A9     1.01 GHz     443   885  2.00     Mali-400 MP2
RK3168    Q2 2014  28nm   2x Cortex-A9     1.5 GHz                          PowerVR SGX540
RK3288    Q3 2014  28nm   4x Cortex-A12    1.8 GHz      980  3873  3.95     Mali-T760 MP4
RK3126/28 Q4 2014  40nm   4x Cortex-A7     1.3 GHz                          Mali-400 MP2
"MayBach"          28nm   8x Cortex-A53                                     OpenGL ES 3.0-class

* RK3188-based deviced running at 1.6 GHz (probably reflecting the use of the original RK3188
  rather than the cost-reduced RK3188T) show a relatively high amount of variation in benchmark
  scores between devices and runs, probably reflecting thermal throttling or other scheduler
  characteristics.

The RK3066 was a relatively high-performance chip at the time of its introduction (second half of 2012), and was successful in the mid-range of the white-box tablet market, as well as gaining design wins with companies like HP. The relatively high clock frequency Cortex-A9 cores on a 40nm process, as well as the Mali-400 MP4 GPU, constrained its power efficiency.

The RK3188 (in practice more often the lower-clocked RK3188T in a cost-reduced package) was introduced as the logical successor to the RK3066 addressing the higher-performance part of the white-box tablet market as well as being adopted in brand name models from Asus and others. Although Cortex-A9 cores are not very power-efficient, efficiency is improved by the use of a relatively advanced 28nm HKMG process at Global Foundries. Rockchip has benefitted from the fact that it was one of the few companies with plentiful wafer supply in 2014, being one of the few customers of GlobalFoundries while many of its competitors faced a very tight capacity environment at TSMC and to a lesser extent other foundries. In 2014, the RK3188T has been observed not only in more performance-oriented tablets, but also in significant numbers in cheaper tablets with relatively low-cost and low-quality components outside of the processor, being seemingly out of place. This scenario probably unfolded because of shortages of tablet processors due to the tight foundry capacity environment outside of GlobalFoundries, while GF may have offered low prices for wafers in the face of excess capacity.

The RK3168 was announced in 2013 as a power-efficient dual-core processor, but only arrived in Q2 2014 with relatively limited adoption among signs that its power efficiency leaves something to be desired.

The dual-core Cortex-A9 RK3026 and RK3028 appeared in numerous low-end tablets in 2014, while the pin-compatible RK3126 and RK3128, which are due to appear in Q4 2014, will finally see Rockchip transition away from the relatively inefficient Cortex-A9 to the more efficient (in terms of cost and power consumption) Cortex-A7.

Finally, the RK3288 is an ambitious high-end processor utilizing four Cortex-A17 (technically Cortex-A12) cores also manufactured at GlobalFoundries. The RK3288 was delayed and for some time pitched to manufacturers of media boxes and other devices amongst indications that hardware work-arounds were required to circumvent hardware issues related to the chip. Reports suggest power consumption and heat production can be problematic. The RK3288 has recently appeared in the Geekbench database in several entries for the Teclast P90HD tablet. Results show performance roughly comparable with Allwinner's A80, with memory performance lower than the A80 and significantly lower than other competitor's chips that also use a 64-bit or dual-channel memory interface, including smartphone platforms. One TV box result shows more acceptable memory performance, probably as the result of a faster DRAM frequency, although still falling short of the performance of smartphone platforms like Exynos 5430 and Snapdragon 801. A relatively steep fall-off in game performance at higher resolutions can be explained by a memory bandwidth bottleneck imposed by the less-than-optimal memory controller. When not constrained by memory bandwidth, the Mali-T764 GPU provides excellent game performance, although the exact nature of the Mali-T764 GPU (a model number not used by ARM) remains in doubt.

Despite the announcement by ARM that the latest version of the Cortex-A12 core is equivalent in performance to Cortex-A17 and the name Cortex-A12 will therefore by retired, a comparison of Geekbench results for the Cortex-A12-based RK3288 with the real Cortex-A17-based MT6595 shows a not insignificant performance difference in pure CPU performance when corrected for clock frequency of about 13% in favor of Cortex-A17, with Cortex-A15 in the middle. This suggests RK3288 does not use the latest version of Cortex-A12 to which ARM referred when making the performance comparison to Cortex-A17.

Qualcomm


Qualcomm has dominated the entire higher-end part of the smartphone SoC market in recent years, largely based on leverage of its patent royalty schemes which are based on the total selling price of a device, enabling Qualcomm to coerce most well-known device manufacturers to use Snapdragon chips for a large proportion of their line-up. More recently, Qualcomm has started targeting the tablet space. Clearly, its integrated 3G/4G modem technology and patent royalty leverage gives it opportunities to penetrate 3G/4G-enabled tablets, but Qualcomm has also been targeting WiFi-only tablets for which it does not have direct patent royalty leverage.

Chip      Arrival  Fab    CPU              Clock speed Geekbench     Multi  GPU          Modem
                          configuration    (typical)   JPEG C.       core x
APQ8064    2013     28nm   4x Krait 300    2.0 GHz       1035  4207  3.22x  Adreno 320   -
MSM8026    2014     28nm   4x Cortex-A7    1.2 GHz                          Adreno 305   -
MSM8074    2014     28nm   4x Krait 400    2.36 GHz                         Adreno 330   -
 
MSM8226    2013     28nm   4x Cortex-A7    1.19 GHz       461  1791  3.85x  Adreno 305   3G
MSM8926    2014     28nm   4x Cortex-A7    1.19 GHz       466  1883  4.04x  Adreno 305   4G
MSM8974-AC 2014     28nm   4x Krait 400    2.45 GHz      1273  4969  3.90x  Adreno 330   4G

Qualcomm's modemless applications processors for WiFi-only tablets are generally variants of smartphone SoCs that do have an integrated baseband. Snapdragon platforms that have modemless counterparts include Snapdragon 400, 600 and 801, while Snapdragon 805 is also technically a modemless processor that might be applicable to WiFi-only tablets.

For tablets with integrated 3G or 4G, Qualcomm uses smartphone chips from the Snapdragon 400 and Snapdragon 800 series. The Cortex-A7-based versions of Snapdragon 400 are power-efficient SoCs comparable in performance to MediaTek's offerings with a reasonably fast GPU. Qualcomm has been leading the integration of 4G modems into SoCs and dominates that part of the smartphone market, which it can also apply to 4G-enabled tablets.

The Snapdragon 800 series has long been the performance leader in the high-end smartphone SoC market outside of Apple, dominating high-end smartphones. This product line is also being used in some tablets from brand-name manufacturers such as Samsung. The Snapdragon 800 series is characterized by relatively high CPU performance, reasonable power efficiency, wide memory interfaces with high bandwidth, and a high-end mobile GPU able to drive high resolutions. From a chip cost standpoint, the series is expensive to produce because of a relatively large die area, but this affects Qualcomm only slightly because of the virtual monopoly it has had from the leverage its patent royalty schemes, which allows it to maintain high margins.

Samsung


Samsung has a fairly extended history developing Exynos SoCs for devices such as smartphones and tablets. A few years ago, when the baseband/modem was generally not yet integrated with the applications processor in performance-oriented smartphones, Samsung used a significant number of Exynos application processors in international versions of its flagship smartphones such as the Galaxy S II. Later, although Samsung prominently announced the use of new high-performance Exynos chips in new flagship smartphones, actual shipments were overwhelmingly dominated by Qualcomm Snapdragon-based variants of the same model. Only recently in 2014 has Samsung started to again use more of its own Exynos chips (including Exynos 3470, Exynos 5430 and Exynos 5433/Exynos 7 Octa) in new smartphones. Samsung also uses Exynos SoCs in tablets, primarily WiFi-only models.

Chip         Arrival  Fab    CPU                   Clock speed Geekbench   Multi   GPU                Memory  Modem
                             configuration         (typical)   JPEG C.     core x                     bus

Exynos 4210  2011     45nm  2x Cortex-A9           1.2 GHz                         Mali-400 MP4       2 x 32  -
Exynos 4212  2011     32nm  2x Cortex-A9           1.2 GHz                         Mali-400 MP4       2 x 32  -
Exynos 4412  2012     32nm  2x Cortex-A9           1.6 GHz       486  1290  2.65   Mali-400 MP4       2 x 32  -
Exynos 5250  2012     32nm  2x Cortex-A15          1.7 GHz                         Mali-T604 MP4      2 x 32
Exynos 5420  2013     28nm  4x Cortex-A15/A7       1.9 GHz      1212  4337  3.58   Mali-T628 MP6      2 x 32  -
Exynos 5260  Q2 2014  28nm  2x + 4x Cortex-A15/A7  1.7 GHz                         Mali-T624          2 x 32  -
Exynos 5422  Q2 2014  28nm  4x Cortex-A15/A        1.9 GHz                         Mali-T628 MP6      2 x 32  -
Exynos 3470  2014     28nm  4x Cortex-A7           1.4 GHz                         Mali-400 MP4       32      4G
Exynos 5430  Q3 2014  20nm  4x Cortex-A15/A7       1.8 GHz      1053  4910  4.66   Mali-T628 MP6      2 x 32  -
Exynos 5433  Q3 2014  20nm  4x Cortex-A57/A53      1.4-1.9 GHz  1376  6130  4.45   Mali-T760 MP6      2 x 32  -

Some Exynos SoCs, including Exynos 4412 and Exynos 5420, have been sold to parties outside of Samsung such as Chinese tablet manufacturers.

The use of the relatively power-hungry ARM Cortex-A15 core has made it a challenge for Samsung to preserve power efficiency, generally limiting the use of these Exynos processors to tablets. Samsung' s implementation of big.LITTLE has become more optimized over time, progressing to the ability to do full Global Task Switching and implementing improvements in power efficiency. Power use is also helped by newer versions of the Cortex-A15 core, process improvements (e.g. 20nm), and reducing the maximum clock rate for the Cortex-A15 cores (which were sometimes set in an unbalanced way at a high speed for marketing purposes, at the cost of the practical experience such as shorter battery life).

Sources: Geekbench browser

Initial version (November 7, 2014): Geekbench CPU benchmark results still have to filled for most SoCs
Updated (November 8, 2014):  Add Atom Z2560, MT812x benchmarks, correct description of MT8121.
Updated (November 9, 2014): Improve Intel section.
Updated (November 13, 2014): Provide more CPU benchmark scores, some other improvements.
Updated (November 18, 2014): Provide CPU benchmarks for Qualcomm and Samsung chips.
Updated (November 27, 2014). Improve Samsung section, add CPU benchmarks, fix RK3288 CPU configuration, add MT8752 CPU benchmarks, comment on variation in JPEG Compress CPU scaling scores for MT8752 and Allwinner A33.
Updated (November 30, 2014). Add note about MT8121.
Updated (December 5, 2014). Add NVIDIA section, other tweaks.

1 comment:

MichaƂ Fularz said...

Great, detailed post. Keep it up!