Which one of the two is more stressed in the game?

Considering that I have a core 2 due 4300 @ 2.5GHZ and a Radeon X1950 pro.

I would like to see the effect of overclocking and the additional cores. It seems to me the game is bottlenecked on my system and I guess since the game was originally designed for a triple core console, it can be the lack of the third core. Would somebody with a quad core processor test this?

I tried to disable a core from the PC setting in the game but it didn't take effect and the game was still using two cores!