PS4: What are the rumoured specs capable of?

[Chark]

Slimebeast said:

It's gonna have a much stronger GPU than the 7670, it's as simple as that. The 7670 is awful and would mean that the PS4 is only three times faster than the PS3.

I believe the PS4 will be 8 to 10 times faster.

Yeah, I was expecting something like the 7750 or 7770