3dfx isn't dead yet, and they will continue to support their cards for a little while longer, at least, so you should be good for another 6 or so months. At that point, you'll probably be interested in upgrading anyways, so I wouldn't worry about it. Keep your Voodoo4, as it will surely serve your purposes for a while yet. If you ever find that it doesn't, then by all means sell it and buy something else.