/etc/X11/xorg.conf

Section "Device"
        Identifier      "nVidia Corporation G94 [GeForce 9600 GT]"
        Driver          "nvidia"
        Vendorname      "NVIDIA Corporation"
        Boardname       "Geforce 9600 GT"
        Busid           "PCI:5:0:0"
        Option          "UseDisplayDevice"              "DFP-0"
        Option          "DPI"                           "96 x 96"
        Option          "NoLogo"                        "true"
        Option          "OnDemandVBlankInterrupts"      "true"
        Option          "DynamicTwinView"               "false"
        Option          "ModeValidation"                "AllowNon60HzDFPModes, AllowInterlacedModes"
EndSection

Section "Monitor"
        Identifier      "L1920P"
        Option          "DPMS"
        Horizsync       31.5    -       64.0
        Vertrefresh     56.0    -       75.0
EndSection

Section "Screen"
        Identifier      "Default Screen"
        Monitor         "L1920P"
        Device          "nVidia Corporation G94 [GeForce 9600 GT]"
        SubSection "Display"
                Depth 24
                Modes   "1280x1024"     "1024x768"      "800x600"       "640x480"
        EndSubSection
        Option          "MetaModes"     "DFP-0: 1280x960 { ViewPortIn=1280x960 +0+32 }
EndSection

Xorg.0.log (auszuege)

[ 13913.782] (**) NVIDIA(0): Option "ModeValidation" "AllowNon60HzDFPModes, AllowInterlacedModes"
[ 13913.782] (**) NVIDIA(0): Option "DynamicTwinView" "false"
[ 13913.783] (**) NVIDIA(0): Option "OnDemandVBlankInterrupts" "true"
[ 13913.783] (**) NVIDIA(0): Option "MetaModes" "DFP-0: 1280x960 { ViewPortIn=1280x960 +0+32 }"
[ 13913.783] (**) NVIDIA(0): Option "UseDisplayDevice" "DFP-0"
[ 13913.783] (**) NVIDIA(0): Enabling 2D acceleration
..
[ 13914.594] (II) NVIDIA(0): Mode Validation Overrides for LG Electronics L1920P (DFP-0):
[ 13914.594] (II) NVIDIA(0):     AllowNon60HzDFPModes
[ 13914.594] (II) NVIDIA(0):     AllowInterlacedModes
[ 13914.596] (WW) NVIDIA(0): No valid modes for "DFP-0:1280x960{ViewPortIn=1280x960+0+32}";
[ 13914.596] (WW) NVIDIA(0):     removing.
[ 13914.596] (WW) NVIDIA(0): 
[ 13914.596] (WW) NVIDIA(0): Unable to validate any modes; falling back to the default mode
[ 13914.596] (WW) NVIDIA(0):     "nvidia-auto-select".
[ 13914.596] (WW) NVIDIA(0): 
[ 13914.596] (II) NVIDIA(0): Validated MetaModes:
[ 13914.596] (II) NVIDIA(0):     "DFP-0:nvidia-auto-select"
[ 13914.596] (II) NVIDIA(0): Virtual screen size determined to be 1280 x 1024
[ 13914.624] (**) NVIDIA(0): DPI set to (96, 96); computed from "DPI" X config option