8800gts causing problems in oblivion?

Im having this problem with Oblivion, about 30 min into playing ill go outside or something or even just randomly, everything will slow down except i am still able to look around at normal speed but the characters go to turtle speeds and so does my jumping as well as navigating through the windows. now the framerates are perfect but just the action in the game slows way down. oh and the sound skips (broken record) when this happens too.

maybe over heating issue, driver, bad mem?
i have all the newest drivers for the 8800 gts and patch for oblivion. the heat out of the video card isn't really that hot when i feel it.

Specs: ASUS A8V-VM SE K8M890 939 mobo, venice 3400+, WINTEC AMPO 1GB 184-Pin DDR SDRAM DDR 400 (PC 3200) , xfx 8800 gts, ocz 600w power supply.

this setup was also having problems with GRAW in the sound too. and the game was running super slow. maybe a crappy onboard sound?

does anybody think they know what might be happening?