I have tried a few steam games, Penny Arcade 1, Team Fortress 2, Left 4 Dead Demo. PA1, and TF2 works great. L4D however does not. The screen size is set to 640x480 and displays nothing, but the mouseover sounds work when you mouse around and wander over a button. The lead in video works, but after that you have to force quit. I am impressed with the team fortress 2 performance, seems as good as crossover games. I will "test" some more... I downloaded some DirectX 9.0c Shader 2 screensavers to exercise Parallels 4, and they work, but when they run, they reduce the size of the screen to 640x480 from whatever it was ( I usually run 1280x800 ) just like L4D does. strange. MacBookPro early 2k8 2.5ghz C2D 15.4" 4GB - Parallels 4 Clean XP Pro sp3 2GB 2 cores 256MB video shared net, Upgraded from Parallels 3. Seems to be working to spec.