I dont really play games on my Macbook, but what I would suggest to you is to completely skip installing or using CrossOver to play games. I'm assuming that CrossOver is an emulation engine for Macs, it would be better if you installed Boot Camp and installing Windows XP / Vista natively on your Mac; that way your games would not have to worry about any type of compatibility issues, as all computer games will work just fine on Windows XP. Give it a try, it would be alot easier on your system, and you could play some games with the native graphics chip on your Mac.