GPU Results and Conclusion

Although we took only a very brief look at CPU performance from the Snapdragon 820's custom Kryo cores, we were able to test the graphics capability of the SoC's Adreno 530 GPU against some additional comparative results.

GPU performance is an area where previous Snapdragon processors fared well, and the Adreno 530 is said to offer up to 40% higher performance than the previous 430 found in the Snapdragon 810. Equivalent power savings are also prominently featured with the new GPU core, but once again the battery life/thermal aspects of this new SoC can't really be tested until shipping hardware is in the hands of reviewers.

For now we can only take a broad look at the capability of this new core with existing benchmarks, though it must be pointed out that the advanced features of the Adreno 530 (such as OpenGL ES 3.1+ support) won't be taken advantage of with most of the existing games and benchmarks.

GPU Performance

You may notice that we have selected only fixed resolutions for these tests to even the playing field between generations of SoC GPU cores, as the varying native screen resolutions – though more realistic – would skew the results too much to provide an adequate glimpse of the relative performance of this new GPU core.

GFXBench Offscreen – T-Rex

The T-Rex test is based on OpenGL ES 2.0 and includes textures, material, geometry and particle effective that were highly detailed at the time of release. The graphics rendering engine features planar reflection, specular highlights and soft shadows, providing a good workout even for flagship smartphones and tablets. Offscreen tests are run at 1080p, regardless of the device’s native resolution, and are best used to compare the performance between competing silicon, not competing devices.

The Snapdragon 820's Adreno 530 GPU had such a strong showing here compared to the field that I can't help but wonder if this in an aberration. Part of the problem with these limited hands-on sessions is that we can't go back and re-test like we can when we have more time with the hardware. Still, if these results hold up it's a glowing start to the GPU benchmarks for the 820.

GFXBench Offscreen – Manhattan

Manhattan was the first benchmark to utilize OpenGL ES 3.0 features and uses a nighttime setting with a lot of external illumination to stress the GPU. It uses a deferred rending engine with multiple render targets for the geometry pass, includes both diffuse and specular lighting, uses depth shadow maps, bloom, depth of field and quite a bit more. 

Here again the Snapdragon 820 and Adreno 530 graphics dominate this offscreen test, and again I have to wonder how these results will hold up with further testing. Once review hardware of a shipping smartphone powered by the 820 SoC is available all of this should become clear. For now we will forego the remaining GFXBench results and move on to 3DMark.

3DMark

Use 3DMark Ice Storm Unlimited for chip-to-chip comparisons of the hardware inside your device without vertical sync, display resolution scaling and other operating system factors affecting the result. In Unlimited mode the rendering engine uses a fixed time step between frames and renders exactly the same frames in every run on every device. The frames are rendered in 720p resolution "offscreen" while the display is updated with small frame thumbnails every 100 frames to show progress.

Ice Storm Graphics test 1 stresses the hardware’s ability to process lots of vertices while keeping the pixel load relatively light. Hardware on this level may have dedicated capacity for separate vertex and pixel processing. Stressing both capacities individually reveals the hardware’s limitations in both aspects. Pixel load is kept low by excluding expensive post processing steps, and by not rendering particle effects.

Graphics test 2 stresses the hardware’s ability to process lots of pixels. It tests the ability to read textures, do per pixel computations and write to render targets. The additional pixel processing compared to Graphics test 1 comes from including particles and post processing effects such as bloom, streaks and motion blur. The numbers of vertices and triangles are considerably lower than in Graphics test 1 because shadows are not drawn and the processed geometry has a lower number of polygons.

The purpose of the Physics test is to benchmark the hardware’s ability to do gameplay physics simulations on CPU. The GPU load is kept as low as possible to ensure that only the CPU’s capabilities are stressed. The test has four simulated worlds. Each world has two soft bodies and two rigid bodies colliding with each other. One thread per available CPU core is used to run simulations. All physics are computed on the CPU with soft body vertex data updated to the GPU each frame. The background is drawn as a static image for the least possible GPU load. The Ice Storm Physics test uses the Bullet Open Source Physics Library.

Here the Snapdragon 820 is dragged back down to earth, though the results are skewed far enough in the opposite direction that additional questions are raised. Who would have thought that pre-production hardware could have been experiencing inconsistent performance between benchmarks? These results are poor, and I have to wonder if thermals were a factor given the short timeframe of the graphics benchmarks. So how did the 820's CPU fare in the same test?

This time the performance is more in line with expectations, and the Snapdragon 820's four custom Kryo cores manage to improve on the octa-core performance of the previous SD810.

Basemark X

Basemark X is the world’s most popular benchmarking tool for evaluation and cross-platform comparison of gaming and graphics performance between Android, iOS and Windows Phone 8 smartphone and tablets.

Basemark X is the only vendor-independent benchmark that utilizes the real-world game engine Unity which is very popular among game developers. This means that it scores correlate exceptionally well with real-life gaming performance.

Basemark X includes two game-like graphics tests: Dunes and Hangar. Both tests contain heavy graphics content rendered with detail and complexity, thus pushing the measured device to the limit. The polygon counts in test sequences are up to 911,000.

On the high setting the Adreno 530 in the Snapdragon 820 managed the highest score among the devices tested, and finished 4th in testing at medium quality. This is a win for the Adreno 530 – especially if these improved results come with the promised power savings.

Basemark OS II – Graphics

Basemark OS II is a system-level All-In-One benchmarking tool designed for measuring overall performance of smartphones and tablets from all platforms, including Android, iOS and Windows phone 8.

The benchmark features a comprehensive suite of tests including system, internal and external memory, graphics, web browsing, camera, battery and CPU consumption.

For our final graphics test we have the 820 reference platform losing out to the previous 810 platform hardware, and after the up and down results from these GPU benchmarks this only seemed appropriate. I can't help but wonder how much thermals affected these results. More time (and a controlled thermal environment) would be needed to verify this.

Conclusion

The results presented here – and particularly the GPU benchmarks on this page – provide a mixed impression of this new SoC. There are certainly some impressive results, but also some that seem either too good to be true, or are too low to trust. The pre-production hardware the press had access to might have something to do with these, as the software on the machines was likely not completely optimized for this new SoC.

But the story with the Snapdragon 820 is far more involved that just some simple CPU/GPU benchmark results. The move to a custom quad-core design and the advancements in DSP from this new SoC promise to provide higher efficiency, and much improved battery life, than prior generations. It was a surprising move by Qualcomm to look past the marketing aspect of CPU core-count and instead champion the improved per-core performance of a quad-core design.

In a marketplace that competes with Samsung's 8-core SoCs the Snapdragon 820 has the potential to provide an efficient alternative that could fare well, but only if it ships in flagship hardware in 2016. The lack of Snapdragon 810 devices in 2015 can't be ignored, and a lot is riding on the success of this followup silicon. Of course there's far, far more to the story than these benchmark numbers, not the least of which is the all-new X12 modem with its advanced wireless features (including Cat 12/13 network speeds and tri-band Wi-Fi with 2×2 MU-MIMO).

It's always fun to try out new hardware before it hits the market, but a quality mobile experience is far more than the benchmark data. I have confidence based on the new emphasis on efficiency and power consumption that we will see the Snapdragon 820 on more devices in the coming year than we saw with its predecessor, and at that time we'll have a far better idea of what kind of real-world experience this new SoC provides. I'll look forward to the chance to re-test the 820 on shipping hardware and explore the additional features not covered here.

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