What drivers are you using? try the new 5.30 Detonators and make sure your refresh rate is at least 85HZ (if you monitor supports this at the chosen resolution). If you appear stuck at 60HZ then try HZ Tools
That's probably as good as it will get as I could never get rid of it "completely" with my Anni Pro.
I now have a Asus GTS and although not very much faster, it is a much more complete product. The move to a .18 micron GPU core does wonders for the heat / power issues of the original Together with other minor revisions appears to make it work very well, (smoooooooooth) in everything I've tried so far including UT. Excellent