I made changes based on this post:
http://forums.guru3d.com/showthread.php?t=230676
I installed the latest BETA Drivers today, and after that, when I ran "stat fps" in ut2k4, fps was in the 30's with the changes listed in that post, with no stutter, and when I went back to default settings in the ini file, fps was back up to around 288 fps, and no more stutter with the beta drivers.
I have all the Video options maxed out in UT2004, and running at 1920 x 1200.