intendevo la sezione video : questa sezione

Section "Screen"
Identifier "Default Screen"
Device "Matrox Graphics, Inc. MGA G400 AGP"
Monitor "BenQ FP731"
DefaultDepth 16
SubSection "Display"
Depth 1
Modes "1152x864" "1024x768"
EndSubSection
SubSection "Display"
Depth 4
Modes "1152x864" "1024x768"
EndSubSection
SubSection "Display"
Depth 8
Modes "1152x864" "1024x768"
EndSubSection
SubSection "Display"
Depth 15
Modes "1152x864" "1024x768"
EndSubSection
SubSection "Display"
Depth 16
Modes "1280x1024" "1152x864" "1024x768"
EndSubSection
SubSection "Display"
Depth 24
Modes "1280x1024" "1152x864" "1024x768"
EndSubSection
EndSection

da questa sezione dipende la risoluzione video
il resto se va devi lasciarlo come era