Uhuh then you need to go read the ATI forums, they are full of people complaining about lots of games giving stuttering video.
And i also suffer with bad Stutters only online when using the latest version of Zone alarm pro.
Also getting mouse corruption in 2d as soon as i click on the advanced tab in display settings, others have confirmed this and it seems to be a bug if you use win98 or ME.
Boy i wish i had checked those forums before buying, i would have stuck with the GF4 TI4200 128mb.
Having said that it looks much better and plays fast but it is a pain in the arse.