1. First, make sure you have the proper Modeline in your Monitor Section:
Section "Monitor"2. Make sure your Screen include the Option UseEDID and ExactModeTimingsDVI like so:
Identifier "Default Monitor"
HorizSync 31.5 - 80.0
VertRefresh 56.0 - 75.0
DisplaySize 722 406
Modeline "1280x768" 79.464 1280 1360 1488 1664 768 771 778 798 -Hsync +Vsync
EndSection
Section "Screen"3. And of course, make sure you use the nvidia driver:
Identifier "Default Screen"
DefaultDepth 24
Monitor "Default Monitor"
Option "UseEDID" "false"
Option "ExactModeTimingsDVI" "true"
SubSection "Display"
Depth 24
Modes "1280x768"
EndSubSection
EndSection
Section "Device"
Identifier "Default Device"That's it.
Driver "nvidia"
Option "NoLogo" "True"
EndSection