honestly you have to compensate in some way to run more wows on a system. Even the people who say 'I never lag in Dal' will also often note their FPS is around 30 and their Background FPS are capped at 10 or lower, some times down to 5. hehe. I would recommend not having the screens the same size maybe? If that is what you are doing, make one render in a small area (fill rate can help cause even if you are rendering 1440x900, if it only fills up an area 360x250 then the buffer flips are faster which are choke points in rendering. Lower some of the graphical settings on the window you are not looking at that often. If you are noticing some frame stops and hard drive grind than maybe setting up system links for your wow accounts if you have them copied over instead would help. You have to give a bit to get a bit in the end.