Ich kann Deutsch schlecht aber vielleicht Sie wollen /etc/X11/XF86Config4 editieren:

Code:
...

Section "Screen"
     Identifier "Screen0"
     Device     "Card0"
     Monitor    "Monitor0"
-->  DefaultColorDepth 24
     SubSection "Display"
          Depth     1
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
     SubSection "Display"
          Depth     4
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
     SubSection "Display"
          Depth     8
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
     SubSection "Display"
          Depth     15
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
     SubSection "Display"
          Depth     16
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
     SubSection "Display"
          Depth     24
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
     SubSection "Display"
          Depth     32
          Modes "1024x768" "800x600" "640x480"
     EndSubSection
EndSection

Section "DRI"
     Mode 0666
EndSection
-- Ed