I tried installing the 40.41 and 30.82 drivers last night and repeated the process 3 times. I conclude:
The 40.41 drivers are slightly faster in UT2003 benchmarks (and for me, 5% faster in 3DMark2001se). However, the 30.82 drivers actually appear 'smoother' in UT2003 (and Operation Flashpoint, the only other game I tested.)
When I say 'smooth', I mean if I spin the camera with the mouse, even though the frame rate was between 40 and 110fps, the 'feel' and 'look' was definately smoother with the older drivers. That is why I installed and reinstalled them a few times to compare, and ended up keeping the 30.82s to play the game.
Both sets of drivers exhibited occasional pauses or slow downs for no particularly good reason (Eg. nothing special happening on screen, or complex area visible.)