I installed the driver that ubuntu offered me. When I downloaded and installed the latest "official" drivers from AMD site, it downgraded it, instead of upgrading it. I couldn't even run Normal Visual Effects because of it. By the way, I successfully ran Half Life 2 Deathmatch (well with a lot of bugs). So the problem shouldn't be in performance, since cs doesn't even need opengl running. It runs in software mod too. But just to make it clear, I did run cs in opengl.