Can my FPS get better?

I have Intel i7 930@2.80GHz, and Sapphire HD 5830 1GB DDR5, and my CPU is not on 2.80 GHz, its on 2.00GHz. In Modern Warfare 2, my FPS go from 300, 200, 140, 90 to a minimum of 55 FPS on everything being set to extra and with shadows and all the other stuff. If i increase multipliers for my CPU and make it go 2.80 GHz will it stabilize and improve my frames per second? And dont tell me to lower my details, or resolution, just tell me will it help with FPS?