I have a rig I build myself a couple years ago. It runs fine, except that during some games I get a studdering. At first I thought it was the video drivers, I stripped them out and reinstalled and it did not fix it. I swapped out my video card for another one and the problem is still there (so its not the video card). I swapped out the ram and it still happens. I am all out of ideas, so if you have one, let me know.
Nvidia 680i LT SLI Mobo
4 gigs OCZ PC2 6400 (Vista Upgrade 5-6-6)
Nvidia (BFG) 8800GT and/or Nvidia 7900GTX (not at the same time)
Windows 7 - 64 bit.
I uploaded a video of the studdering. Its only 3 megs, so check it out. The game is Planetside (which you should play, its awesome). But the studdering is ruining my gaming.