An updated D3DDrv.dll is floating around (and now local mirrored), put it in UT2003/System directory (backup original file). It will offer a fix for S3 Savage 4 cards, z- pixel fog bug and ATI/driver bug with vertex range fog.
Gamer's Hell Local Download:
UT2003 S3/ATI Fix / Patch (<1 MB)
Just remember to backup original file, OK?