Overall the Radeon is a "better" - notice, in quotes - card than the nVidia because of various rendering and anti-alias issues. This affects just the current generation of cards. Your system setup is pretty solid, so you should have no problems with what you have. Just FYI, the card will ONLY help with previewing the images in the viewport, and have nothing to do with the actual rendering of the final image. That is all processor/memory.