[Naito]

In the BIOS, set your FSB to 333MHz and lower the core ratio from 12.5 to 10. This should give you a core clock of 3.33GHz. The temperatures should be safe with the stock cooler, but you won't want to go any higher. See if this boosts FPS. Makes sure you carefully monitor temperature though.

PS. I will not be held responsible if your PC catches fire and explodes (although, very unlikely).

EDIT: What speed is your RAM? You should try to get a 1:1 ratio between FSB and RAM. This should give you a good boost. But ONLY do this if you know what you are doing!