does it helps if you add : Load "GLcore" in the Modules section ? http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=289328, have an example with a working configuration (on linux and xfree86 :-/ ) Also /var/log/XFree.0.log would help to figure if it is a configuration error or a bug in xfree Cheers Alban