Yesterday, while playing through Half-Life 2 (this time at 1600 x 1200 ... :-D), I noticed that, after playing for a while, the game began stuttering. Strangely enough, changing the graphics and audio settings didn't make things any better. Even down at 640 x 480 with everything as low as it would go, the game was still quite choppy. So I got looking around the web, and began wondering if my new AMD dual-core processor was the problem.
I found a number of pointers to CPU drivers, dual core optimizers, a hot-fix from Microsoft, and more. But one forum post in particular caught my eye. It has links to all of the aforementioned fixes, and contains a number of tips on how to get games to work properly in a dual-core environment. This morning, I installed the latest nForce chipset drivers from nVIDIA, as well as the dual-core optimizer from AMD. The nForce drivers have unfortunately made my SATA hard drives appear as removable, which is odd but understandable considering that SATA drives support hot-swap functionality. And the dual-core optimizer seems to have removed the stuttering (though I haven't played as long today as I did yesterday; I still need to investigate whether this has truly fixed the problem or not).
Anyways, if you happen to have a dual-core processor, and are concerned about game stuttering, I highly recommend the forum post above. Perhaps the steps I've taken so far will fix the problems I was seeing.