The new fad is the more cores the better. However I'm finding that time and time again I must set my processor affinity down to 1 CPU in order to get most of my games to run without massive stuttering and glitches. It is not a framerate issue b/c I'm pulling in 60 FPS on 60Hz yet the games still stutter. The moment I set the affinity the games are smooth as silk.
It seems that not many games are actually utilizing multi-cores or are designed with multi-threading in mind.
This leads me to another point. Is it possible that the current threading model needs a major overhaul so that it is simpler to both use and debug? Perhaps developers stray away from threading because it does bring up many many issues if not handled correctly. Those issues, in turn, take time and thus money to resolve making the development slower and more costly.