Well. This is a very double-sided issue here. 4890 is, at the moment, a better performer than 5770. Driver tweaks may tighten the ~5-10% gap a bit, even make 5770 better, but the 5770 is even without those tweaks a worthy buy in theory. Barely, if at all noticeable difference in performance, and DX11 support. Problem is, there are always less and less "real" PC games, as in not console ports. DX11 has
very interesting and good features, but consoles render DX9 only, and will, for who knows how long. I would go for the 5770 if I were to choose from those two, but I've just upgraded to this piece of junk