Since when the fequency, the quantity of RAM or the number of cores means performance?
Think of the Pentium4, the PS3 or PS2 with so few MB and most MP3 players that embed dual core microcontroller.
And why talking about performance, what makes a good game? Quality of it's graphics?
No.
It's the gameplay!
What do you need to obtain a good gameplay? Good software developers first (they do miracles with crappy hardware)
- Good man-machine interface, no lag. No need for 10 cores to do that.
- The rest depends on the style of the game but the quality of graphics comes after the concept of the game itself.
That's why people still plays ugly Counter Strike or Quake 3 or Tetris.
That's also why riding a bicycle is a good game, the gameplay is excellent

I totally agree with Valve, evolution of PCs (and consoles) is too slow, analog gamepads' quality was a regression compared to any model's radio remote control. Hire me please, Valve

p.s. good game does not mean good sales