I see where you are coming from, i don't see why efficency comes into the equation though..
The games played on a console and on a PC are different in design anyway.. PS3 and Xbox 360 run at 720p and PC games run a 1080p and higher.. (apart from Dark souls)
I guess the point i was trying to make was purely from a performance standpoint....there seems to be a lot of people trying to directly compare a PS4 GPU to a PC GPU, but it just can't be done.
So until we actually see some games for ourselves (and i don't mean all these pre-release demo videos) we can't judge how good they're going to look (or not) in comparison to PCs