here's an interesting note: I just upgraded my video card. because my onboard video was the same brand, it left the onboard graphics enabled and turned all five (!) video ports on. A sad side effect was it disabled 3d / 2d acceleration! Plus everything was showing in device manager as installed correctly, but catalyst control center was giving an error "card not found" even though there were two of them, and it wasn't listed under display properties either. I had to disable the onboard video. As a side note i will be enabling it again later to see if i can get hybrid crossfire to work.
my new card is a ati hd5770. This thing is F-A-S-T! unfortunately borderlands doesn't like it and it crashes the driver. Other than that i'm running everything at 1080p full specs.