I wonder what kind of FPS it gets in Doom3.
I think it also has to come down to the system itself. You could have a 100 GHZ CPU but if your HD and Graphics card sucks your going to have a crappy FPS. Your computer needs to be in harmony.. Infact a very high end CPU with low end memory, gpu and hd would make make things worse because your system would constently be caching via the page file in windows to keep up with the instructions.
So with that CPU.. you would need a graphics card that hasnt been created yet hehehe.. Maybe a graphics card that has a small hard drive to help cache for the lack of memory it has! Oooh! time to call my patent lawyer!