GPU And Gaming Performance
Mobile GPU performance is becoming increasingly important as people begin to see their phones and tablets as portable gaming machines. This section explores GPU performance with several synthetic and real-world game engine tests. To learn more about how these benchmarks work, what versions we use, or our testing methodology, please read our article about how we test mobile device GPU performance.
The Snapdragon 810 v2.1 SoC in the OnePlus 2 gives its Adreno 430 GPU a slight 5 percent bump in clock frequency compared to the first revision 810 used in the HTC One M9, which happens to correspond to the performance difference between the two phones in the graphics portion of this test. The Adreno 430 is no match for the newer Imagination Technologies PowerVR GT7600 in the iPhone 6s Plus, but it's a huge upgrade over the Adreno 330 used in the OnePlus One, with a peak performance 64 percent higher. Qualcomm has been focused on improving ALU performance for several generations now, so it's no surprise that the biggest improvement comes in the second graphics test that focuses on pixel operations, where the OnePlus 2 sees a 78 percent gain over the previous generation. The Adreno 430 also holds a 38 percent advantage over the Mali-T760MP8 GPU in the Galaxy S6 edge+ in this portion of the test, despite the Mali’s higher clock speed. The Mali GPU is able to pull about even with the OnePlus 2’s Adreno GPU in the first graphics test that focuses heavily on vertex processing rather than pixels, though.
The physics test focuses on CPU performance and uses a data structure that requires random memory access patterns. Just like we saw in the AndEBench memory latency test, both Snapdragon 810 devices perform poorly, providing further evidence that the memory controllers in the latest Snapdragon SoCs are optimized for sequential access patterns.
Basemark X can use up to five times as many triangles as 3DMark: Ice Storm Unlimited, which tips the scale in favor of the Mali GPU in the Galaxy S6 edge+; it performs 22 percent better offscreen than the OnePlus 2 in Dunes, but the greater number of pixel operations in Hangar allow the Adreno 430 to close within 10 percent. Another reason why the OnePlus 2 falls behind in Basemark X is because it throttles its GPU more than the Galaxy S6 edge+ (Basemark X runs longer than 3DMark). This is also why its performance advantage over the OnePlus One shrinks to only 30 percent overall in the offscreen test. It does throttle a little less than the HTC One M9, at least.
The finishing order remains the same when running the benchmark at the high quality setting. The main difference is that the Adreno 418 GPU in the LG G4 and Moto X Pure Edition runs into a memory bandwidth limitation (the Snapdragon 808 uses LPDDR3-933 memory) that limits overall performance.
The two different versions of GFXBench Manhattan use a game engine based on either OpenGL ES 3.0 or OpenGL ES 3.1 to render a variety of lighting and pixel effects. Despite its ALU advantage, the Adreno 430 in the OnePlus 2 is a little slower than the Mali-T760MP8 in the Galaxy S6 edge+ in the OpenGL ES 3.0 version but jumps back out front when running the updated OpenGL ES 3.1 version offscreen. The OnePlus 2 also outpaces the HTC One M9 by 10 to 15 percent, a little more than the 5 percent difference in clock speed can account for. It's also more than twice as fast as the OnePlus One, whose Adreno 330 GPU does not support the newer OpenGL ES 3.1 standard.
Manhattan uses deferred rendering for its lighting effects, which is highly dependent on screen resolution. It's no surprise then to see the phones with QHD screens, including the LG G4, Moto X Pure Edition, and Galaxy S6 edge+, all take a performance hit when rendering at their native resolution.
T-Rex is based on the older OpenGL ES 2.0 standard and has a closer balance of vertex and pixel operations. Once again the Galaxy S6 edge+ performs a little better than the OnePlus 2. While neither Snapdragon 810 device throttles its GPU in the short one-minute T-Rex offscreen test, the OnePlus 2 makes better use of its A57 CPU cores, which helps it perform 23 percent faster than the One M9.
The GFXBench Alpha Blending test stresses rasterization and memory bandwidth. The Adreno 430 in the OnePlus 2 performs well here, helped along by the streaming bandwidth optimizations in the Snapdragon 810's memory controller. We should see similar results in the Fill test, which stresses pixel processing and memory bandwidth, and sure enough the M9 tops the chart. Something happens with the OnePlus 2, however, since it’s quite a bit slower than the M9. We noticed some larger than usual performance fluctuations in some of the other memory bandwidth sensitive tests too, causing us to rerun tests and reboot the phone more than usual to get consistent data. We’re not sure what’s causing this inconsistent behavior.
As we mentioned previously, Qualcomm has been focused on improving ALU performance for several generations, giving its Adreno GPUs a clear advantage over ARM’s Mali and Imagination’s PowerVR architectures in this particular area. The OnePlus 2 is about 2.5x as fast as the Mali powered Galaxy S6 edge+ and even 18 percent faster than the newer iPhone 6s Plus. All of the devices are capped at the display’s 60Hz refresh rate when running the test onscreen.
The Adreno 430 in the OnePlus 2 is clearly a big step up in performance relative to the Adreno 330 in the OnePlus One. The 5 percent clock speed advantage and better thermal management help it outperform the HTC One M9 that runs the earlier revision of the Snapdragon 810. It's a little slower than Samsung's Galaxy S6 family of phones in most tests, but not by a lot. While the OnePlus 2's peak performance is quite good, we still need to evaluate its sustained performance in the next section to see if it can deliver a good gaming experience.