The overlooking of the relevant product information for PowerVR's cores keeps leading to strange rationalizations about Apple's GPU decisions and unnecessary narratives about their ultimate ambitions by some commentators.
Two cases in point in a row now:
One, while most, including myself, initially expected the iPhone 6 devices to go with a wider six cluster configuration, the claim of 50% better performance over the four cluster iPhone 5s was used as "confirmation" of a six cluster A8 GPU even after the revelation of ASTC support had people agreeing on an architecture upgrade to Series6XT. Imagination had clearly stated that the jump from Series6 to 6XT was, by itself, quite specifically a 50% bump in the common benchmarks used for mobile graphics.
For A8X, a consensus for some existed that it still had to be the 12 TMU standard GX6650 core despite the screaming-for-a-reasonable-explanation fill rate results had been known for quite a while. And, now that the inescapable conclusion of a 16 TMU core and the eight cluster configuration logically follows, some rationalization is being forced out about how Apple themselves must've taken the PowerVR four cluster core floor plan and doubled it when Imagination had specified (just not publicly productized as is not always preferable depending on the project/partner) scalability to eight clusters with Series6.
Now, amid the rationalizations for incorrectly guessing the number of clusters Apple picked for the GPUs in A8 and A8X, the unnecessary narrative that Apple's obvious need for their own GPU engineers for implementing new PowerVR cores so surprisingly fast should also signify a definite intent to replace PowerVR is stretching the speculation too far at this point.