Quote Originally Posted by Djarid
As has been posted in another thread if you span your desktop and use maximiser to resize / relocate the 2nd / 3rd instance of WOW then you will not get the 2nd screen performance hit.

I was getting 80%+ CPU utilisation off my second instance before spanning the desktop... now it is less that 40%
I had 100% usage of duo core cpu by 2 clients with minimal graphic settings on both and like 10 fps. After setting up horizontal span I run 5 clients, one of them is on max settings. All maximized, it lags only in big crowded cities, otherwise 50 fps on each.