Your hardware isn't the problem, it's the way Parallels implements some (probably depracted/legacy) Direct3D API call to initialize fullscreen. Since I'm on OS X 10.7.1, I'm forced to play D2 on Parallels (prefer it over BootCamp) as Rosetta support has been removed from Lion. Diablo 2 does work, you just need to run D2 in a window. You can add "-w" to the command line and it will run windowed. I also like to add "-sndbkg" for enabling sound/music to continue playing when the window loses focus. Inside Diablo, you can set the resolution to 800x600. There's a "-nofixaspect" command line argument which lets you resize other than 4:3 aspect ratio, but I do not recommend it. I've found it runs best in it's native window size at 800x600, resizing has significant performance issues. I'm fairly confident this is D2's coding rather than Parallels. If you're curious at how fast it is running, you can use the 'fps' command in game (press enter and type it). Newer versions of Diablo (I think 1.10+) use the /framerate command. Runs like a champ on Parallels 7 (I'd imagine previous versions too) both on my new MacBook Air (240+ fps) and iMac (700+ fps). Get your fix before Diablo III!