Here is the full quote:
"I think the Playstation 4 is going to raise the quality of the applications on all levels, lift it all up. Compared to the PS3, the PS4 uses a more generic CPU that anybody can draw out the performance for. The PS3, on the other hand, has very high peaks on just some of the elements and it is hardware that is more difficult to handle. It's fun to wrestle with that and try and get it to put out that performance. Once we start work on Gran Turismo for the PS4, perhaps it will be GT7. At that point, I guess we'll start to look of the peak performance for the PS4."