I'm not sure if I'm adding anything to this discussion but I wanted to 3box (eventually 5 if I can) without using another pc or squeezing windows on my existing monitors. I have a spare 19" so I brought an nvidia 8400 512mg pci (only slot i had available) and popped it in. Win 7 RC 32 (I'll be installing 64) recognized the card after a reboot and I setup the 3rd monitor. I configured keyclone and ran 3 windows of wow from 3 different folders on different harddrives. I can move the 3rd window around all of the monitors without seeing fps hits but I usually run my slaves at 20fps anyway. withouth much further testing the only thing I noticed was that I couldn't run it full screen (monitor was 1280x1024) so the window was only running at 1024x800. My main vid card is an Nvidia 8800 running the main window at 1920 on a 28" monitor and my second slave on a 20" widescreen running 1024x800 full screen.

I only have 3gigs of ram but running 3 wow's I still had about a gig of ram free so not sure if that hampered my performace or not.

What should I do to test if the 2nd gpu is being used by Wow?