I've played the mac version of Wow on my previous intel iMac as well as on a macbook and my current hackintosh. There's always a slight FPS drop compared to the windows version on the same hardware (wow installed in windows either boot camped or normally on a hackintosh PC). The drop in FPS is because the opengl code of wow isn't as fast as the directx code, you can check that with -opengl parameter in windows too. There's no much sense in emulating windows wow in os x as it'd have to use opengl too. The difference in FPS isn't so big it alone would make sense for dual boot though. I think the OS X port by blizzard is good enough.