Choppy Gameplay

[porsche911r]

hey guys iv just got a new pc i got it as a present (JuHU!!!) but i am having some issues play need for speed pro street. I play FEAR and Age of empires 3 very smoothly but need for speed is very choppy i dunno why i tried to change alot of things but no luck. i thought it was related to hardware acceleration but i cant access that it says my drivers do not allow me to.

my pc specs are as follows:

AMD 5200 X2 Oc'ed to 2.92 using water cooling
Nvidia Sparkle 8600gts in SLi
Hiper 880 PSU
MSI K9N SLi
Apple 20 Cinema Display

these are my pc specs i hope you guys can help me please.

 

[Bruce2]

Is you graphic card driver up to date? How much ram you have?

 

[porsche911r]

yes i got the latest driver but i installed the ones which vista automatically installs i have got 2 GB of Kingston Value Ram DDR2.