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The PS4 has roughly the same hardware as a mid-range gaming PC - without the overhead of highly abstract APIs like DX and OpenGL; that's why consoles can get away with weak CPUs, their graphics APIs aren't CPU intensive. (Mantle is a step close to console-like low overhead APIs but it will probably never be as efficient.)
Seriously, have you seen games like Infamous: Second Son?
https://www.youtube.com/watch?v=7cF_J4qvvOM
and that is an early game before developers get to know the hardware inside out.