Random stuttering only in one game

Hi guys. I've got an extremely irritating problem with bad company 2 and the vietnam expansion. The game runs flawlessly on my new system and i absolutly love playing on max settings with high fps.
There is just 1 annoying problem where i get this strange random suttering after every 10 - 15 minutes or less. it will be a stutter of about 5 frames that last about 1 second each frame, before returning to the flawless game again.

This is the only game i have experienced this on and its putting me off from playing it. If anyone knows about this i would greatly apprechiate some help!

My system specs are

I7 950 3.4ghz
6GB RAM
XFX Radeon 6950 2GB
Sound blaster audigy
Vista
600w PSU