I've been thinking of adding a 2nd display to my iMac coreduo 1.83ghz, with radeon x1600 128mb video. It's either going to be a 19" widescreen or a 22" display. My question is how much of a performance hit will it be adding the display? I do play games on this computer (WoW) and I do use a lot of CS2 and Macromedia suite. I'm assuming this won't impact my processing performance, but I'm almost certain that my framerates in WoW will go down, but by how much?