A change in the production process at this point would be unlikely, as Global Foundries doesn't have their 20nm process ramped up yet and there wouldn't be enough capacity to accommodate a new family of APUs, GPUs and the custom silicon for other companies like Sony and Microsoft. Maybe a bit later on in 2015 they'll start looking at it.
What might be happening is a change in the board layout and of the cooling setup, because the PS4 is one hot puppy. The PS3 is currently running on the 45nm process, so I'd expect a drop to 28nm over there.




