the cheapest ati pci card you can find. You won't get any sort of video accelleration on the secondary monitor anyway (I had 2 for a while). My primary at the time was a voodoo3 and the secondary was an ati rage pro 2 (mach64 based), I didn't have any problems with it in windows at all. When I tried to get linux to see the voodoo3 as the primary card (I am a linux newbie, and have been for over a year), that is where I ran into trouble.