Course you can always capture as raw AVI and reencode later640x480 capture resolution, however, you need a pretty fast computer to run it.
I wouldnt think the video card to be that big a player when it comes to video capture but more, the CPU/memory subsystems?pretty fast computer to run it.
and I have a Nvidia GeForce FX 5200 graphics card, i'm not really into game graphics, but the graphics are pretty good.