CPU scaling with Geforce 8800 Series
 

Most games are GPU bound, although recent RTS game Supreme Commander does need a fast CPU to make it enjoyable. Legion Hardware compares 11 system running G80 series card:

"Although the GeForce 8800 GTX is best suited to high-end systems, it can be utilized quite well on slightly slower processors. Of course we are not talking about slow processors here, in fact quite the opposite. However, the 1600x1200 resolution showed almost no performance variations between the eleven configurations with the FSAA and Aniso settings enabled.

http://www.legionhardware.com/document.php?id=618&p=0