The PowerVR GX6450 GPU in the iPhone 6 Plus is the direct descendent of the G6430 GPU used in the ZenFone 2 (also used in the previous generation iPhone 5s). These GPUs have the same ALU performance, processing 256 FP32 FLOPs/clock. The ZenFone 2 runs its GPU at either 457MHz or 533MHz under load, and while we do not know the exact peak GPU frequency for the iPhone, it does lie within this range. This means we should see similar performance in pixel shader bound workloads. Where the GX6450 gains an advantage, is in front of and behind the unified shader cores, improving vertex processing and pixel fill rate, respectively.