most of games use still just ONE or TWO cores ( and it is borrrrrring for quads) if u overclock your quad that should gain your FPS on each game. For most games your Quad is worth nothing more than standard Core 2 Duo 
or Athlon X2 (this is sad true )
clock speed isn't everything, you can't say a quad will be as slow as a dual core if you don't overclock your quad, because quads have far higher cache than dual cores
no matter what you do, a quad core will always be faster than a dual core.
