6600 GT beats the X800 Pro in most cases except in the Source engine where the X800 Pro has a major advantage. Unless you are a religious CSS player, get the 6600 GT for it is much better, or better yet, get the 6800 vanilla. The 6800 is cheap these days and blows away the 6600 GT and the X800 Pro. Believe me, I have an X800 Pro and am not happy with it at all.