Hello, I'm hoping someone else has gone through this problem and found what the problem is. I have a Macbook pro 17" with NVIDIA 330M and 8GB of RAM, running 10.8.2 since its release. For the past 2 days, ANY game I play (official Steam releases of L4D 1 or 2, Call of Duty Black oPS, Non steam Aspyr's COD 4 ), start off nice and smooth, but begin cutting down to very low fps after maybe 10 or 15 mins to the point where it's unplayable. I have been playing L4D for over a year on this system without a hitch before. I usually restart the system and relaunch the game. It works fine for the same length of time and slows to a crawl again. My automatic graphic card switching is off (I just doubled check). If I don't restart the computer, even if I relaunch the game the problem is still there. I checked with Activity monitor and besides the main game which takes like 60 to 85% of CPU there's nothing else that takes any real resources. The problem started appearing on the same day I downloaded both the Mac Gamestore .app and Call of Duty Black ops. I don't see how that could have done anything, but I can't see anything else that might have caused this either.