If you play Team Fortress 2
, you'll see an update
go through with a new option. Multi-core support has been added but it's turned off by default. To enable, you go to Options->Video->Advanced and check Multicore Rendering. This should boost framerates for those with 2 or more cores on their CPU. I'm going to have to check this out later today as I just popped in my Quad-Core not too long ago. Yay for engine advancements!