I have the same processor and graphics card as Astrocat but no stutters.
As other posters have suggested get the March dll (this was the last release).
http://www.wikiupload.com/download_page.php?id=82467
V sync on works best for me and this card with single frame rendering.
Also make sure you have just a single core set to run IL2.
Goes without saying but I hope your PSU is up to running these cards I have 60 amps on the 12v rails !!!!