fglrx drivers have to be installed. Use of Ubuntu's Restricted Drivers Management console is not necessary, but can lead to sucess too.

To list the supported powerstate:

DISPLAY=:0 aticonfig --lsp

To enforce a powersaving state of the graphics chipset (X is the number of a supported state):

DISPLAY=:0 aticonfig --set-powerstate X

# xorg.conf (xorg X Window System server configuration file)

Section "ServerLayout"
        Identifier     "Default Layout"
        Screen      0  "defaultscreen" 0 0
        InputDevice    "Generic Keyboard"
        InputDevice    "Configured Mouse"
EndSection

Section "Files"
EndSection

Section "Module"
        Load  "glx"
        Load  "GLcore"
        Load  "v4l"
        Load  "dri"
EndSection

Section "DRI"
Mode 0666
EndSection

Section "InputDevice"
        Identifier  "Generic Keyboard"
        Driver      "kbd"
        Option      "CoreKeyboard"
        Option      "XkbRules" "xorg"
        Option      "XkbModel" "pc105"
        Option      "XkbLayout" "de"
        Option      "XkbOptions" "lv3:ralt_switch"
EndSection

Section "InputDevice"
        Identifier  "Configured Mouse"
        Driver      "mouse"
        Option      "CorePointer"
        Option      "Device" "/dev/input/mice"
        Option      "Protocol" "ImPS/2"
        Option      "ZAxisMapping" "4 5"
        Option      "Emulate3Buttons" "true"
EndSection

Section "Monitor"
        Identifier   "Highscreen MS 1795PII"
        VendorName   "Highscreen"
        ModelName    "MS 1795PII"
        HorizSync    30.0 - 86.0
        VertRefresh  47.0 - 120.0
        Option "DPMS" "true"
EndSection

Section "Device"
        Identifier  "ATI Technologies Inc RV350 AR [Radeon 9600] rev 0"
        Driver      "fglrx"
EndSection

Section "Screen"
        Identifier "defaultscreen"
        Device     "ATI Technologies Inc RV350 AR [Radeon 9600] rev 0"
        Monitor    "Highscreen MS 1795PII"
        DefaultDepth     24
  SubSection "Display"
                Depth           24
                Modes           "1024x768@85" "800x600@85" "640x480@85"
        EndSubSection
EndSection

http://wiki.ubuntuusers.de/Konsolen-Aufl%C3%B6sung

1. Add vesafb,vga16fb and fbcon in /etc/initramfs-tools/modules
2. update-initramfs -u
3. in /etc/modprobe.d/blacklist-framebuffer , comment vesafb,vga16fb
4. in /etc/modules, add vesafb
5. in /boot/grub/menu.lst add e.g. vga=0×0318 to set console resolution