The Huawei Mate 8 Review

The on-screen T-Rex tests show an even larger performance improvement as we’re getting 2.5x the performance of the T628 in the Kirin 925 and 935. The 220MHz (32%) clock advantage alone isn’t able to account for the performance increase and the remaining factors coming from the addition of a new LPDDR4 memory controller are also far greater than what we’ve seen from the T760, leaving us with the only viable explanation that ARM’s new GPU generation is able to show some solid improvements in terms of performance at the same clock and physical configuration.

In the off-screen tests we see similar scaling improvements of the Mali GPU in the Kirin 950, but now we see a more apples-to-apples comparison between it and the competition. It looks like Kirin 950’s configuration lands it at a similar performance level as the Adreno 420 found in last year’s Snapdragon 805 devices.

3D Power

As we’ve hopefully come to learn over the past year, raw performance is not the only factor that determines how good a device is in gaming, but also what kind of power levels the phone is able to sustain and what kind of total efficiency level the SoC + platform are able to deliver.

We continue to make usage of Kishonti’s GFXBench T-Rex and Manhattan tests to determine the efficiency levels of the current generation of GPUs. 

In the T-Rex test we see that the Mate 8 and the Kirin 950 are able show a very reasonable power consumption of around 3.64W at 41.6fps. This results in an efficiency estimated at about 11.40 fps/W, almost on par with the Exynos 7420 in the Galaxy S6. The difference here is that HiSilicon targets a much more sustainable power level at maximum frequency while the latest generation Qualcomm and Samsung SoCs exceed power envelopes that would fit in mobile devices.

An interesting question for the efficiency of the Mali T880 is how it compares to the T760 in the Exynos 7420. Here we’re seeing to different design philosophies as HiSilicon prefers to push for high clocks at narrower GPU configurations while Samsung goes for wider implementations at lower clocks (Although they’re still relatively high at 700+MHz). Here we see that going narrower and clocking higher is a disadvantage as we’re trading off die size for efficiency. At a similar power consumption of 3.36W the Exynos 7420 is able to achieve 45.6 fps for an efficiency of 13.67fps/W, higher than that of the Kirin 950’s even though the latter has a process node and architectural advantage.

In Manhattan 3.0 we actually see the Kirin 950 beat all other devices in terms of power efficiency. Although the T880 features 50% more ALUs than previous Mali GPUs, the total power is still lower than what we see in T-Rex as it comes at 3.18W. This bodes very well for the T880 as we could see even higher efficiency numbers from wider and lower clocked implementations such as the one in the upcoming Exynos 8890. ARM continues to have a good efficiency advantage over Qualcomm’s Adreno GPUs when it comes to computational heavy workloads. We’ll have to wait a bit more to see how the new Snapdragon 820 and the Adreno 530 fare in this aspect.

Similar to the A72 cluster, it looks like the GPU cluster is also capped in terms of minimal supply voltage as the GPU stops scaling down after the 650MHz frequency point which is rather unfortunate and means that we’re not seeing the best showing of the SoC as the lower frequencies are the ones most often used in everyday scenarios.

Overall, the Kirin 950 seems to showcase very competitive efficiency at its highest operating points while still maintaining power envelopes that are fit for a smartphone.

Device Thermals

Peak power and power efficiency are what determine the overall sustained performance of a device. In 3D workloads we saw that the Mate 8 and the Kirin 950 are able to show exemplary peak power fitting smartphone phone factors so we should be expecting quite good sustained performance from the Mate 8.

Indeed when looking at the battery rundown test of the Mate 8 we see that it’s able to maintain near peak performance for the whole duration of the run, only throttling down to lower frequencies for small periods of time. This again bodes well for the Kirin 950 as it looks like its GPU configuration is well justified and well balanced. The fact that the Mate 8 only sports a 1080p screen enables the phone to achieve some of the best sustainable performances in games among current Android devices.

A new kind of measurement test that I conjured up for our SoC evaluations and first published in the review of the Nexus 6P was a CPU throttling benchmark. Here I use a CPU power virus with two threads (loading up 2 CPU cores) over a duration of little over 25 minutes. The point of this exercise is to determine long-term performance in comparison to the maximum performance capable of the device. We’re not measuring the work done here but simply want to compare just how usable the overdrive frequencies of each SoC’s CPUs are. As each device features different thermal dissipation characteristics, the results will always vary even if two devices use the same SoC.