[gorbs]

is your cpu a quad core at 2.66 ? so that would mean each core is 70mhz. or a core2duo. this game runs flawlessly on my c2d 2.6 laptop with an 8600gt and 2 gigs of ram. what type of memory is it ? a good quality gaming memory like crucial, ocz, corsair etc. if not that might be the problem.

i run xp on my laptop and gaming rig. gaming rig is an e6750 c2d cpu, 8800gt, 4 gigs of crucial tracer memory. i added the extra two for the bling factor (blinking led's) than any performance reason because the game ran fine on two gigs.

i do remember some talk of single cpu v/s duo core running this game thats why i asked about your cpu being a quad core. really i am grasping at straws to try to help give you other avenues to look at to get your game running because it is such a cool game and very graphics intensive. what other games are you playing ?

edit: how big is psu powering everything? again grasping here.