Thursday, April 30, 2015

More details emerge about Cortex-A72 CPU core

Recently, more details have become available about the performance improvements implemented in ARM's Cortex-A72 core, which is a replacement for the high-performance Cortex-A57 core. Apart from the gains from using a more advanced process such as 14/16 nm FinFET, Cortex-A72 also implements fairly significant micro-architectural improvements affecting performance per cycle and power efficiency. AnandTech has published a detailed overview of these improvements.

Cortex-A57 based on Cortex-A15 and not fully optimized for power-efficiency

The Cortex-A57 CPU core, which was announced in 2012, has significant similarities to Cortex-A15, ARM's long-standing high-performance 32-bit CPU core, which has been known for relatively high power consumption. As such, it is not unexpected that improvements on the Cortex-A57 architecture (in the form of the Cortex-A72) have proven to be possible. Cortex-A57-based SoCs  such as Snapdragon 810 have been known to throttle, being forced to reduce the clock speed due to excessive heat production and power use, resulting in reduced sustained performance. Apple's A7 and A8 processors use CPU cores that most likely have strong similarities with Cortex-A57, but which exhibit little throttling due to a lower maxium clock speed, a lower number of cores and other factors related to the the chip design.

Increased level of sustained performance

ARM has made available a number of slides detailing the improvements in sustained performance and power efficiency in Cortex-A72 over Cortex-A57. On a 28 nm process and similar clock speed, ARM's charts indicate a roughly 20% improvement in power reduction. 

Sustained performance is expected to be higher than Cortex-A57, implementations of which (such as Snapdragon 810 and Exynos 5433, and to a lesser degree Exynos 7420) have suffered from an inability to maintain high clock speeds and throttle back to a relatively low speed due to heat production and associated power consumption. ARM gives a figure of sustained 750 mW operation per core on a 16FF+ process with a clock speed around 2.5 GHz.

In terms of IPC (instructions per cycle), ARM's information shows improvements in all instruction-level performance segments, with a 1.16x improvement for "analytics", 1.38x for cryptography, 1.50x for memory, 1.26x for floating point and 1.16 for integer compute. The increase in memory performance appears to be significant.

Improved single-core performance evident in early Geekbench results

Early Geekbench results for the MT8173 SoC from MediaTek, which includes two Cortex-A72 cores, give an indication of practical peformance of the Cortex-A72 core, although the exact clock speed the Cortex-A72 cores are running at is hard to determine. The following table shows single-core performance from a recent MT8173 Geekbench entry, comparing it to Exynos 7420 as used in the Samsung Galaxy S6. Both use 64-bit AArch64 mode.

SoC                        JPEG   Dijkstra  Lua   Mandelb. Stream SGEMM SFFT
                           Compr.                          Copy
28nm? MT8173 (Cortex-A72)  1429    1287     1675  1750     2217    979  1345
14nm Exynos 7420           1475    1082     1409  1147     1993    954  1379
The MT8173 easily matches the single-core performance of Exynos 7420, while showing significant improvements in the Mandelbrot floating point subtest and the memory-intensive Dijkstra subtest, and also the Lua subtest. Memory subtest (Stream Copy) performance is also better than Exynos 7420, despite the likely much wider memory interface of the latter, providing clear evidence of the improved memory performance (largely due to smarter prefetching) in Cortex-A72. Overall, since the MT8173 results reflects a SoC using 28 mn or perhaps 20 nm process technology, while Exynos 7420 uses Samsung's leading-edge 14 nm FinFET process, the ability of the MT8173 to beat Exynos 7420 in single-core performance while using a less advanced process is impressive and illustrates the performance improvements in the Cortex-A72 core.

Reduced silicon area results in lower cost

Cortex-A72 has a silicon area that is 10% smaller than Cortex-A57 on an equivalent process, while delivering improvements in performance and power efficiency. Already SoCs have been announced or described that utilize Cortex-A72 cores, such as MediaTek's MT8173 for tablets, Qualcomm's Snapdragon 618 and 620 for smartphones, and MediaTek's MT6797 (Helio-X20) for smartphones.

There seems to be a clear trend of using just two Cortex-A72 cores (instead of the four cores used in many Cortex-A57 implementations), reducing cost and maximum power consumption. These are cores are augmented by low-power, small-area Cortex-A53 cores running at a lower frequency. MT8173, Snapdragon 618 and Helio-X20 all use such as configuration.

Use of Cortex-A72 may be more effective than high-clocked Cortex-A53 cores

There are indications that Cortex-A53 cores running at a high frequency (such as implemented in MediaTek's MT6752 and MT6795 (Helio-X10), HiSilicon's Kirin 930 and to a lesser degree in Snapdragon 615 and the announced Snapdragon 415 and 420) run into a power efficiency bottleneck at higher clock speed, due the relatively steep increase in power consumption as the clock speed of the Cortex-A53 core increases above 1.3-1.5 GHz. Solutions that combine a small number of Cortex-A72 with lower-clocked, power efficient Cortex-A53 cores may prove to be a sweet spot in terms of practical performance and power efficiency for mid-range SoCs.

Source: AnandTech (Cortex-A72 Architecture Details article), Geekbench Browser

Tuesday, April 28, 2015

Spreadtrum takes market share in Chinese smartphone market in Q1 2015

DigiTimes Research recently posted a report about smartphone AP (application processor) shipments in China in Q1 2015, indicating that Chinese fabless semiconductor company Spreadtrum gained market share in Q1, mainly based on strength for low-end 3G solutions. According to the report, Spreadtrum's market share reached 17.4% in Q1 2015, while MediaTek continues to lead the Chinese market with 46.8% share, followed by Qualcomm, which increased its share to 23.6%.

In terms of overall shipments, according to DigiTimes unit sales of smartphones by Chinese manufacturers declined significantly by about 30% in Q1 2015 compared to Q4 2014, with manufacturers focusing on export sales suffering the largest declines. Huawei, which is moving towards a strategy of using mainly in-house chip solutions from its HiSilicon division, was relatively unaffected and took market share in the quarter.

Spreadtrum's product line

Spreadtrum's increase in 3G smartphone solution shipments most likely reflects the 28 nm SoC it announced in June 2014, the SC883XG. This SoC features a quad-core Cortex-A7 CPU running up to 1.4 GHz, an ARM Mali-400 MP2 GPU, modem support for TD-SCDMA/HSPA(+) and GSM/GPRS/EDGE with dual-SIM capability, and integration of Spreadtrum's Wi-Fi/Bluetooth/GPS/FM chip technology.

The features of the SoC are extremely similar to MediaTek's successful MT6582 platform, which has been on the market for more than one and a half years. The combination of quad-core Cortex-A7 CPU, Mali-400 MP2 GPU and a high level of integration of other functionality on a 28 nm process appears to deliver good performance and very good power efficiency for cost-sensitive devices.

Spreadtrum also recently announced volume shipments of the SC7731G with 3G modem and the SC9830A with LTE modem. Rather than using Cortex-A53 CPU cores, the new chips continue to use efficient Cortex-A7 cores with Mali-400 MP2 GPU with support for Android 5.

MediaTek's 3G market share impacted by Spreadtrum

The DigiTimes report attributes MediaTek's loss of market share in China in Q1 2015 mainly to Spreadtrum's gains for 3G smartphone SoCs, where MediaTek has had a strong position. However, Qualcomm is likely to be a significant factor as well, with indications from new model announcement by companies such as TCL (Alcatel), ZTE, Lenovo/Motorola and others that MediaTek's late introduction of low-cost 4G solution has hurt the company. The resolution of the Chinese monopoly investigation into Qualcomm is also likely to be a factor.

Additionally, a trend has been noticed whereby second and third-tier Chinese smartphone manufacturers have lost share to the largest first-tier manufacturers in China. Since MediaTek's share among second and third-tier manufacturers has been the strongest, this has hurt MediaTek's shipments.

Projections for Q2 2015

For Q2 2015, DigiTimes expects overall AP shipments in China to increase 17.6% sequentially from the low base set in Q1 2015, although that still amounts to an increase of 18% over the same quarter last year (Q2 2014). DigiTimes expects MediaTek to recover some share to reach 48.4%, with Qualcomm seeing a small decline to 21.3% and Spreadtrum's share declining to 15.2%. DigiTimes attributes Spreadtrum's loss of momentum to pressure from MediaTek's 3G solutions, which probably reflects price reductions implemented by MediaTek after it saw shipments decrease and inventories build.

Sources: DigiTimes Research (smartphone AP shipments in China in Q1 2015), (DigiTimes Research (Chinese smartphone shipments in Q1 2015), Spreadtrum (2014 smartphone chip announcement), Spreadtrum (2015 smartphone chips announcement)

Thursday, April 23, 2015

Details surface about MediaTek's upcoming Helio-X20 SoC

Recently, details surfaced about MediaTek's upcoming Helio-X20 SoC, a high performance offering in the series of Helio-branded SoCs, of which the MT6795 (Helio-X10) is the first member. The deca-core Helio-X20, which has the model number MT6797, has a total of ten CPU cores and is the first mobile SoC with a hierarchy of three clusters of progressively less performance-oriented CPU cores: two ARM-Cortex-A72 cores, four high clocked ARM-Cortex-A53 cores and four lower clocked ARM-Cortex-A53 cores.

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 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

Execution issues at Qualcomm regarding their high-end product roadmap may increase the chances of success of MediaTek's high-end product line. Qualcomm's Snapdragon 810 has some performance issues and has not been a great success, giving MediaTek the opportunity to capture more of the performance-oriented, premium level segment. MediaTek already has Helio-X10 (MT6795) in the market, which has gained design wins, but for which some key characteristics such as power efficiency are still unknown.

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

On 12 May, MediaTek officially announced Helio-X20. Most of the previously known details are confirmed in the announcement. The chip utilizes MediaTek's new CorePilot 3.0 heterogeneous computing scheduling algorithm, with together with the tri-cluster architecture should provide up to 30% reduction in power consumption. The chip has advanced camera features and has an ARM Cortex-M4-based sensor hub processor for better battery efficiency.

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), (Comparison of MT6797 with Snapdragon 810), MediaTek (Helio-X20 announcement), AnandTech (Helio-X20 article)

Updated 21 May 2015.

Thursday, April 16, 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.

Thursday, April 9, 2015

Cortex-A53 based SoCs: MT6735 shows up, power efficiency of MT6752 in question

More and more devices with Cortex-A53-based SoCs, mainly targeting the entry-level and mid-range segments, are coming into the market. Qualcomm's original Snapdragon 410 (MSM8916) has already shipped in large volume, and devices using Qualcomm's Snapdragon 615 (MSM8939), as well as MediaTek's MT6732 and MT6752, have also ramped up. Meanwhile, Huawei is introducing devices using its in-house HiSilicon Kirin 620 SoC.

In the Geekbench database, results for new SoCs that are not yet shipping in end products are showing up, including MediaTek's delayed performance-oriented MT6795 (Helio-X) and the appearance of a result for the MT6735, MediaTek's new offering for the cost-sensitive segment.

In this post, I will be examining updated benchmark results for these SoCs, as well as taking a look at battery life benchmarks. Power efficiency of Cortex-A53-based products does not appear to be as good as hoped, with significant variability present (for MT6752-based devices, for example).

Snapdragon 410 smartphone platform appears to be slightly updated

Qualcomm's Snapdragon 410 (MSM8916) smartphone platform, which has performance flaws probably associated with the use of an early-revision Cortex-A53 core, seems to have been slightly updated in some recent models and reference designs, with a minor performance improvement due to a slightly higher clock speed (1.21 GHz vs 1.19 GHz) and what appears to be somewhat improved memory performance, while still being limited to 32-bit ARMv7 mode.

This improvement could be the result of a new revision of the SoC with a few hardware tweaks and an associated reference design, although it does not appear to be a radical redesign that would, for example, upgrade the Cortex-A53 core to allow use of the ARMv8 instruction set. Qualcomm's modem-less stand-alone version of Snapdragon 410, APQ8016, does appear to be a new design that does not have the restrictions of the smartphone SoC and can run in full 64-bit mode (it targets development boards and tablets).

MediaTek's MT6735 shows up in Geekbench

A single result for MediaTek's MT6735  SoC has appeared in the Geekbench database. The MT6735 is MediaTek's much-needed offering for the entry-level market with integrated LTE modem with world-mode support. It has been described as a cost-down version of the MT6732, which is a quad-core Cortex-A53-based SoC with a Mali-760 MP2 GPU. The MT6735 downgrades the GPU to a Mali-720 (probably Mali-720 MP4) which appear to be associated with lower manufacturing cost.

The MT6735 has an upgraded r0p3 revision of the Cortex-A53 core which, according to Linux kernel commits by ARM, fixes a few hardware errata which might improve performance and efficiency over previous revisions. The Geekbench entry shows the MT6735 running at a maximum clock speed of 1.3 GHz, which is lower than the 1.5 GHz of the MT6732. This could be due to the use of the cheaper 28LP process at TSMC, instead of the higher-performance 28HPM.

Notably, the device is running in full AArch64 mode, which has pros and cons for performance, but is unusual for a cost-sensitive platform because those platforms are usually sensitive to the higher demands on the memory subsystem from the increased addressing size and addressing space in AArch64 mode. Those platforms until recently only used AArch32, the 32-bit variant of the ARMv8 instruction set. The use of AArch64 makes comparisons a little difficult because it affects different benchmarks (including different Geekbench subtests) in different ways. The Android version (5.0) is also different from most existing entries for comparable SoCs, which use Android 4.4.4.

MT6752's power efficiency average, with high variability

According to most reviews that have appeared for MT6752-based devices such as the Meizu M1 Note and other devices, power-efficiency and battery life is generally average, with significant variability between devices. The Cortex-A53 core, although delivering higher performance, clearly seems to be associated with reduced power efficiency as compared with Cortex-A7 in SoC such as MediaTek's MT6582 and Qualcomm's Snapdragon 400, which generally have excellent battery life.

The variability in MT6752 performance could reflect variable performance yields in the manufacturing process, with some chips performing better (with lower voltage and power at a given frequency) than others. Frequently, chips are separated into speed bins and lower-performing ones may be sold as a cost-reduced variant running at a lower maximum clock speed. Indeed, a review of the Acer Liquid Jade S containing the MT6752M, which is likely from the poorest-performing speed bin of the MT6752, reports relatively poor battery life and some heat production. This suggests the variability may be quite large.

Update (21 May 2015): Recent information suggests that CPU power efficiency for this SoC is relatively high when CPU power is demanded, but standby efficiency (including wireless network standby) may be less impressive.

Overview of Geekbench results for Cortex-A53-based SoCs

The following tables show Geekbench results for a recent, representative entry for each Cortex-A53-based SoC. The first table below gives an overview of the devices, with SoC, CPU configuration, device model, Geekbench reference number, Android version and the instruction set architecture tested.

SoC                       CPU configuration                  Device               Geekbench Android Arch
                                                                                  reference version
Snapdragon 410 (MSM8916)  4 x 1.19 GHz Cortex-A53r0p0        Samsung SM-G360F     2275416  4.4.4   ARMv7
Snapdragon 410 (MSM8916)  4 x 1.21 GHz Cortex-A53r0p0        Xiaomi 2014817       2181099  4.4.4   ARMv7
Snapdragon 410 (MSM8916)  4 x 1.21 GHz Cortex-A53r0p0        Motorola Moto-E2     2275732  5.0.2   ARMv7
Snapdragon 615 (MSM8939)  4/4 x 1.50/1.0 GHz Cortex-A53r0p1  Samsung SM-A700FD    2274606  4.4.4   AArch32
MT6732                    4 x 1.50 GHz Cortex-A53r0p2        Elephone P6000 O2    2265175  4.4.4   AArch32
MT6735                    4 x 1.30 GHz Cortex-A53r0p3        "bq DENDE"           2268728  5.0     AArch64
MT6752                    8 x 1.69 GHz Cortex-A53r0p2        Lenovo P70-A         2276814  4.4.4   AArch32
MT8752                    8 x 1.69 GHz Cortex-A53r0p2        CUBE T7 (tablet)     2078854  4.4.4   AArch32
MT6795                    8 x 1.95 GHz Cortex-A53r0p2        Alps k6795v1_64_op01 2076054  5.0     AArch64
MT6795T                   8 x 2.16 GHz Cortex-A53r0p2        Unknown              2188071  5.0     AArch64
Kirin 620 (Hi6210)        8 x 1.20 GHz Cortex-A53r0p3        HUAWEI Che2-L11      2269931  4.4.2   AArch32
The Geekbench version used in the entries is 3.3.2 or 3.3.1.

Snapdragon 410-based devices are still limited to ARMv7 compatibility mode. Unusually for a cost-sensitive platform, the MT6735 test device uses AArch64 mode instead of AArch32 mode. Both the MT6735 and HiSilicon's Kirin 620 use a more recent version of the Cortex-A53 core, revision r0p3.

Integer subtest results

The following table shows results for integer subtests from Geekbench.

           CPU          JPEG Compress            Dijkstra                 Lua
                        Single IPC   Multi Par.  Single IPC   Multi Par.  Single IPC   Multi Par.
MSM8916    4 x 1.19      591   1.29  2379  4.03   816   1.09  2122  2.60   614   1.26  2229  3.63
MSM8916    4 x 1.21      602   1.29  2416  4.01   830   1.09  2182  2.63   632   1.27  2267  3.59
MSM8916    4 x 1.21      599   1.29  2404  4.01   739   0.97  2159  2.92   592   1.19  2168  3.66
MSM8939    4 x 1.50 + 4  832   1.44  4962  5.96   942   1.00  3469  3.68   744   1.21  2360  3.17
MT6732     4 x 1.50      842   1.46  3357  3.99  1035   1.10  3049  2.94   740   1.20  3049  4.12
MT6735     4 x 1.30      650   1.30  2563  3.94   712   0.87  1856  2.61   642   1.20  1902  2.96
MT6752     8 x 1.69      954   1.47  5810  6.09  1153   1.08  4817  4.18   850   1.22  2244  2.64
MT8752     8 x 1.69      952   1.46  7527  7.91  1200   1.13  4168  3.47   829   1.19  2294  2.77
MT6795     8 x 1.95     1026   1.37  8071  7.87   992   0.81  3886  3.92  1051   1.31  8075  7.68
MT6795T    8 x 2.16     1128   1.36  8991  7.97  1054   0.78  4159  3.95  1112   1.25  4159  3.74
AArch64 mode as used for the MT6735 and MT6795/MT6795T results has a significant influence, with the IPC (throughout per CPU cycle) for the JPEG Compress and Dijkstra tests being reduced when compared to AArch32 mode, while the IPC of the Lua test appears to be better in AArch64 mode, at least for the MT6795.

The MT6735 scores lower than the MT6732 in the Lua subtest, especially multi-core, even when correcting for the lower clock speed, which is probably the result of a smaller or slower L2 CPU cache inside the MT6735, which is targeted at the entry-level segment. The Dijkstra results are also lower, but that is probably mainly due to the use of AArch64 mode, which imposes a significant penalty on the results of this test.

Finally, while earlier results for the MT6795 showed very impressive Lua multi-core throughout, the result for the recent MT6795T entry is significantly lower (although still respectable). This is possibly due to a smaller L2 cache size in the latest revision of the MT6795T, although other reasons cannot be ruled out.

Memory and floating point subtest results

           CPU           Stream Copy  SGEMM        SFFT         Mandelbrot
                         Single Multi Single Multi Single Multi Single IPC   Multi
MSM8916    4 x 1.19      551    655    258   536   316    1264    450  1.11  1796
MSM8916    4 x 1.21      505    615    267   515   322    1292    456  1.11  1819
MSM8916    4 x 1.21      424    518    247   517   320    1277    451  1.09  1810
MSM8939    4 x 1.50 + 4  581    651    255   678   425    2510    583  1.14  3442
MT6732     4 x 1.50     1000   1187    343   697   430    1728    586  1.15  2329
MT6735     4 x 1.30      944   1034    322   636   403    1574    526  1.19  2102
MT6752     8 x 1.69     1007   1115    375  1123   485    3894    662  1.15  5279
MT8752     8 x 1.69      891   1045    387  1162   486    3902    662  1.15  5280
MT6795     8 x 1.95     1296   2070    484  1536   629    5021    824  1.24  6350
MT6795T    8 x 2.16     1380   2129    543  1847   687    5565    912  1.24  7171
Hi6210     8 x 1.20      575    996    262   819   343    2098    468  1.14  2842
The results show the memory performance advantage of MediaTek's Cortex-A53-based SoCs remains, scoring significantly higher than Qualcomm's existing SoCs, probably due to the use of a faster internal interconnect bus.

The first entry for Snapdragon 410 (MSM8916) running at 1.19 GHz is a Samsung SM-G360F, which appears to use relatively high-clocked memory, increasing memory performance over standard configurations (not listed). The two devices with a 1.21 GHz configuration have different memory performance, with the Moto G2 4G scoring lower than the Xiaomi device, probably due to the use of slower RAM. An impact from the use of Android 5 on the Moto G2 cannot be ruled out.

Sources: Geekbench browser, GSMArena (Acer Liquid Jade S review)

Updated 16 April 2015.