I never bother to register my stuff. It's probably for warranty purposes and updates regarding your video card. When I buy a new video card, it comes standard with whatever factory warranty. As long as I have my invoice I should have no problem. Either the part will work perfectly or it will break down on arrival or later in the week upon using it. I never get extended warranty. Waste of money.
With the latest and greatest stuff coming out all the time, I don't see why I even need to register. I"m always upgrading anyways, hehe. For updates, I just go to the vendors website and download new drivers or new software to be used with the video card.