Would have been interesting for Ars to have asked them how their GPU differs from the IMGTec/PVR IP they acquired besides adding more cores, what did they change?
They give the impression by saying it’s a custom GPU that it’s a from scatch in-house design but it’s unlikely to be the case.
The GPU they were licensing from Imagination was already very tailored to their needs. Apple already had a strong saying in the architecture, in the driver, in the compiler and in the implementation details of the GPU they were buying from them.
Moving to a "custom GPU" was basically Apple saying "Ok, thanks, we are taking over from here".
They give the impression by saying it’s a custom GPU that it’s a from scatch in-house design but it’s unlikely to be the case.