Three-cluster hierarchy extends the big.LITTLE principle
The SoC's ten CPU cores are organized as follows:
- Two Cortex-A72 cores clocked up to 2.5 GHz to provide "extreme performance".
- Four Cortex-A53 cores clocked up to 2.0 GHz for "best performance/power balance".
- Four Cortex-A53 cores clocked up to 1.4 GHz for "best power efficiency".
The different clusters and their separate L2 caches are linked together using MediaTek's MCSI interconnect technology. MediaTek claims higher efficiency than big.LITTLE based designs, which have just two levels of cluster hierarchy.
The triple-level hierarchical design is a significant departure from the symmetric CPU configuration on current MediaTek smartphone SoCs such as MT6795 (Helio-X10) and MT6752, which have eight "equal" Cortex-A53 cores, although MediaTek does have experience with big.LITTLE, for example in the 32-bit MT6595 and some tablet processors.
Reports suggest the chip is manufactured using a 20 nm process at TSMC and will be in mass production as soon as July 2015. This marks MediaTek's first known product manufactured using a geometry below 28 nm.
Other features: ARM Mali-T880 MP4 GPU, dual-channel LPDDR3, world modem
Based on a recent report from Gizchina.com that gives more details about the specifications of the chip, other features include an ARM Mali-T880 MP4 GPU at 700 MHz and a dual-channel 32-bit LPDDR3 memory interface at 933 MHz. The maximum display resolution supported is 2560x1600. The integrated LTE modem has Cat. 6 capability. and also supports CDMA2000/EVDO Rev. A (world modem support). The video processor supports decoding and encoding of the H.265 format up to 4K resolution.
The report suggests the SoC will start shipping to manufacturers this summer with end products reaching stores by late autumn.
Execution issues at Qualcomm may help MediaTek's chances of success in high-end
Meanwhile, MediaTek has come under pressure in the cost-sensitive smartphone SoC market, previously the bread-and-butter of the company, on which Qualcomm is encroaching by gaining market share for low-end devices in China. This is mainly the result of MediaTek's delayed introduction of cost-sensitive 4G SoC solutions.
MediaTek's sales performance under pressure
While MediaTek has made some progress penetrating the performance-oriented smartphone market with SoCs such as MT6752 and MT6795, it has lost ground in the cost-senstive smartphone segment among Chinese manufacturers, which it previously dominated. Although MediaTek's March 2015 sales rebounded from the low level of February, for the second quarter its sales performance is not expected to reach the level of previous quarters (such Q3 and Q4 of 2014). Indeed, the forecast given by MediaTek during its quarterly results presentation for Q1 2015 on April 30 sets sequential growth between -5% and +3% for Q2 2015, which represents a lower level of sales than the level MediaTek was accustomed to in 2014.
Due to a product mix with a significantly lower volume of cost-senstive SoCs, offset by some traction for performance-oriented SoCs, MediaTek's product mix has changed, with overall unit shipments and unit market share for MediaTek declining when compared to the previous year, despite likely higher performance-oriented chip shipments.
Update: MediaTek has officially announced Helio-X20
According to AnandTech, quoting MediaTek, the GPU used is not the Mali-T880 but an as yet unannounced Mali-T8xx series GPU, similar to Mali-T880. Compared to Helio-X10's PowerVR G6200, MediaTek sees a 40% performance improvement with a 40% drop in power.
Sources: CNXSoftware (Helio-X20 article), DigiTimes (MediaTek Q2 sales projection), DigiTimes (MediaTek Q2 2015 quarterly results), Gizchina.com (Comparison of MT6797 with Snapdragon 810), MediaTek (Helio-X20 announcement), AnandTech (Helio-X20 article)
Updated 21 May 2015.