Not sure if you guys know this but there is a modified Nvidia driver set at 3d Guru called - ForcewareUltra 84.66 "Sedona". And boy does this driver scream fps for me.....
My spec
P4 2.4 Northwood (Clocked at 2.602.54)
Pny 6600 GT OC
1024 meg Dual channel Ram (Generic)
Un-installed my old driver set>>> Rebooted used Drive cleaner pro (Free proggie) to get rid of any lingering registry markers then installed this new driver.
Played SH3 and saw a dramatic increase of 15-20 fps. This with riva tuner settings of FSAA@4S and Anisotropy at Force Level 8.
So for you Nvidia freaks out there give this baby a try if you have a compatible card.
Link:
http://www.guru3d.com/
Cheers
Deep Six