Section "Monitor"
        Identifier      "monitor0"
        HorizSync       91.15
        VertRefresh     85.02

        Option          "dpms"
EndSection


....

Section "Screen"
        Identifier      "Screen0"
        Device          "device0"
        Monitor         "monitor0"
        DefaultColorDepth 24
        SubSection "Display"
                Depth           24
                Virtual 1280 1024
                Modes          "1280x1024" "1024x768" "800x600" "640x480"
        EndSubSection
EndSection