2008/12/1 Kevin Kempter <kevin(a)kevinkempterllc.com>:
HorizSync 31.5 - 74.5
VertRefresh 56.0 - 65.0
This is probably your problem. BUT, even better, just delete
everything you've got on your xorg.conf leaving only this:
Section "Device"
Identifier "Videocard0"
Driver "nvidia"
EndSection
X autodetection works really well these days and if it weren't for the
nvidia driver you wouldn't actually need a xorg.conf.
Rui