I picked up Left 4 Dead 2 just recently, and play on my MBP non unibody, I believe the Santa Rosa chipset with the 8600m GT. I do play on bootcamp and have the most recent drivers from Nvidia. I read a lot of posts and seen videos on people having good to great performance. I'm confused because I get 10fps whenever there are zombies around and is pretty laggy if there's a good # of them...I get 40fps when I look at a wall. I tried reducing all the graphics settings including resolution and it doesn't change much when actual zombies are around. The recommended settings gives 2x AA, high textures, medium effects, at 1440x900 I have turned everything except paging to low, No AA, bilinear, vert sync off and even reduced the resolution to 1280x800? It's pretty much at its lowest settings, and I don't understand why its struggling to play. Nothing is running in the background at all. I just want it to be smooth, I can live with less graphics.