That's alas not true: I have to reboot to Windows for WoW raids. Under Linux, during heavy action, my FPS varies too much going from 80 FPS down to below 10 FPS, while under Windows it's varying less often and between 40 and 80 FPS. OTOH disk loading is sensibly faster under Linux, but for raids it's of no use.
(FWIW, my CPU is an i7 920, 6 GB RAM and an nVidia GTX 275, so definitely a good machine for WoW, and a video card with very good OpenGL support under Linux.)
Anyway as eastmen said, high-level playing on such a device wouldn't be possible. My raid interface would occupy all of the screen by itself
WINE is a translator... Does it have a high performance hit?
I've never used it, you see.