What does more power give you between X1 and PS4

[Machiavellian]

the-pi-guy said:
Depending on how much of it is true, not a lot to somewhat a lot. The example that was given was that PS4 could get 60 fps while Xbox One get 30 fps with otherwise same graphics.

This would be interesting if such a range happen but I believe we will not see that much of a gap.  If you compare simular graphics cards today based on the released and rumor specs between the X1 and PS4, the gap is not that large.  I guess one of the keys would be how much each company gets close to optimal performace out of the system.