Do you have a CF capable board and PSU?
I don't get it. If everything is fine, why are you looking for a second video card? I get good frame rates in the one game I play, TF2. When I bought my 20" monitor, I was afraid I would have to get a new video card seeing as I run an 8800GS. I was happy when I didn't have to turn any details down, even after moving from 1280x1024 to 1680x1050. The reason I mention this is because after seeing my framerates, I stayed with my 8800GS and didn't bother looking for a new card. Whats going on that you need a new one?