COD4 proformance issue 7900gtx sli

Hi everyone,

was hoping someone might be able to lend there experience to this issue im having...

machine:
p5n32 se sli deluxe
intel e6600 2.4ghz
2gb 667ghz ram
2x 7900gtx's
650W PSU
7200rpm sata's
XP sp2

when playing COD4 the game runs respectably well.. if looking at a complex area with lots of lighting and smoke and such, while standing still i get average 140-160fps... the second i move my mouse or one of the movement keys the fps drop right down to 25-45 depending on whats on screen at that current moment. i dont have anyone i know personally with a machine with similar spec so i dont know what i should be expecting but the drastic drop in preformance has me wondering is there something holding back my video cards from doing there jobs correctly.

i have similar issues with crysis, with everything on high at 1440x900 i get about 24-30fps standing still but that drops to 14-20fps when im moving to a new location... although if i stay in the same general location the fps will return to a playable 25+

i have tried removing 1 video card and i get almost the same results

COD4 avg 90fps , but when moving 25-30fps
crysis avg 25fps, 14-19fps

have tried alot of drivers currently on 169.28 driver which worked wonders for crysis.

i have seen a few threads with similar issues but not the same... and not the same hardware.. any and all advice is most welcome

Cheers
Inch