Kareem, are you talking about front panel devices like on the creative platinum bundles? If so, I have been using those for about 3 years now. I had the Audigy 2 forever and now the x-fi. I simply...
Since you are building a dual 7800GT SLI computer I am assimung this is going to be a gaming machine. I think getting a dual core processor is a terrible choice. Dual core + gaming simply don't mix...
I think your dual core processor is the likely culprit. I would focus your efforts in that direction. I seem to recall a patch for COD2 and dual core processors but not sure. Give google a whirl...
8X AA is a bit extreme anyway. 4X should clean up the picture but still leave the game playable. AF has less impact on your FPS so you can crank it up if you like to 8x or 16x.