Got an ASUS A7N8X Deluxe, 2400+, 1 GB PC2700 Crucial and an ATi Radeon 9500 Pro. Certain DirectX programs, namely 3DMark2001SE, 3DMark2003 and that MS ralli game (the demo) produce stuttered rendering, meaning a few frames will display fluently, then there will be a very short pause, then a few dropped frames, then back to fluent display. I have no idea why this is. UT2003, UT and other DirectX programs worked flawlessly.
Don't know if it's an A7N8X + ATi problem. I was going to post my problem on the Video board...
<EDIT>After a quick trip to the video forum and then over to Rage3D, I found out that this stutter issue could be solved at this point by throttling back video hardware acceleration a notch (in most cases). It seems the problem is driver-related and ATi is most likely working on it.</EDIT>