You might not be aware of this, but Samsung makes two different versions of the Galaxy S7 handset (and I'm not talking about the Edge and non-Edge versions). And when it comes to GPU performance, there appears to be a huge difference between the two in performance.
The difference is down to the chipset used to power the devices. In the US and China, the Samsung S7 will be powered by a Qualcomm Snapdragon 820 chip featuring an Adreno 530 GPU. The rest of the world gets a handset that is powered by Samsung's own Exynos 8890 chip, which features a Mali-T880 MP12 GPU. The reason for this is that the Snapdragon 820 supports CDMA while the Exynos 8890 does not, and since CDMA is used in the US and China, those territories get the Qualcomm chip.
Benchmark testing carried out by AnTuTu suggests that while the CPU performance between the Snapdragon 820 and the Exynos 8890 is about the same (there is approximately 5 percent deviation between the two), the difference between GPU performance is huge (more than 25 percent).
Now this could be down to several things - ranging from poor driver optimization to slower silicon - but this doesn't change the fact that there's a very real and significant difference between the silicon that Qualcomm makes and what Samsung offers, and it's hard not to imagine that a 30 percent performance hit isn't going to be noticeable.
It's also interesting to note that Qualcomm's silicon is faster than Apple's A9 chip, while Samsung's offering is about the same (Samsung manufactures the A-series processors for Apple).