I'm planning in buying an 27" iMac, for AutoCAD, photo editing and gaming.
Since im forced to run my games on Windows, im wondering how the performance is with games on the bootcamp?
You shouldnt get any problem playing any game in windows 7. There are many videos on YouTube where they play Black Ops, Crysis, SC2 etc.. So you should take a look
It would run the same with bootcamp as it would on a similar specced windows machine. You wont notice any difference. Windows will run like Windows does and games will play like they're supposed to. In other words Windows runs natively. All boot camp does it set the boot system to be able to boot the Windows operating system, hence "bootcamp"!!!
Set up my i7 with World of Warcraft / Various flight sims like DCS A-10, Rise of flight and Cliffs over Dover and they all run as good as a comparable PC.
Crysis: 2560x1440 native on High works fine, sometimes small hickups.
Crysis 2: 2560x1440 native on High (which is the lowest setting in Crysis 2 ) works fine. Higher will cause hickups. 1920x1080 on Very High is also possible, Extreme too but will cause hickups.