The first test measured CPU performance thanks to Geekbench. Eight tests were run back to back to stress and heat up each device. The Apple iPhone 6s Plus, powered by the A9 chipset, had a remarkably consistent score throughout all of the CPU tests (as did the SD-820 on the Galaxy S7 edge). The A9 had the highest single-core score among the chips tested, putting up numbers in the 2512-2529 range. That was followed by the 2307-2341 range of the Snapdragon 820. The latter, packed inside the Samsung Galaxy S7 edge, put up the highest multi-core scores proving that it isn't the number of cores that is important, it is the power of the cores that matters.
While the Exynos 7420 showed a large drop in single-core results (1472-1480), the multi-core scores (5018-5148) were high enough to challenge the Snapdragon 820. The Snapdragon 810 showed signs of throttling as the benchmark scores declined over the course of the eight tests.
During the CPU testing, the iPhone 6s Plus and the Galaxy Note 5 were both cool under pressure at 83°F. The Galaxy S7 edge reached 84°F. The Moto X Pure Edition hit 88°F on the thermometer while the Nexus 6P was the warmest with a reading of 95°F.
Testing the GPU of each phone using 3DMark, the iPhone 6s Plus and the PowerVR GT7600 GPU started with the highest score, faltering a bit over the five back-to-back tests. The phone also was the warmest after testing, hitting 104°F. That was an increase of 16% from its temperature at the start of the test. The Adreno 530 GPU running graphics on the Galaxy S7 edge also showed some stress over the course of the test, but ended up with the highest score, edging out the A9 at the end. The temperature gain after the fifth test was 10%. The Adreno 418 on the Moto X Pure Edition has been criticized and it did finish last in the test. At least there was no rise in the temperature of the device after five rounds.
XDA did note that despite the increase in performance brought by the Snapdragon 820, it still found that the UI on the Galaxy S7 edge suffered from lags, stutters and frame drops. During GPU testing, more frames were skipped while browsing through the Google Play Store when compared with a pair of near stock phones powered by the Snapdragon 810 (Nexus 6P, OnePlus 2). Another issue found the screen randomly freezing, preventing any input from being read in the settings and camera apps. Keep in mind that different handsets could produce different results with the same chipset inside.
Check out the graphs and charts related to this extensive test by clicking on the slideshow below.