#/etc/X11/xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the xorg.conf(5) manual page.
# (Type “man xorg.conf” at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg

Section “InputDevice”
Identifier “Generic Keyboard”
Driver “kbd”
Option “CoreKeyboard”
Option “XkbModel” “pc105″
Option “XkbLayout” “it”
Option “XkbOptions” “lv3:lwin_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 “Device”
Identifier “ATI Technologies Inc RV280 [Radeon 9200]”
Driver “radeon”
BusID “PCI:0:16:0″
Option “UseFBDev” “true”
EndSection

Section “Monitor”
Identifier “iMac”
Option “DPMS”
HorizSync 71-73
VertRefresh 70-140
ModeLine “1280×960″ 122.2 1280 1336 1440 1696 960 961 964 1002 +hsync +vsync -csync
EndSection

Section “Screen”
Identifier “Default Screen”
Device “ATI Technologies Inc RV280 [Radeon 9200]”
Monitor “iMac”
DefaultDepth 24
SubSection “Display”
Depth 1
Modes “1024×768″
EndSubSection
SubSection “Display”
Depth 4
Modes “1024×768″
EndSubSection
SubSection “Display”
Depth 8
Modes “1024×768″
EndSubSection
SubSection “Display”
Depth 15
Modes “1024×768″
EndSubSection
SubSection “Display”
Depth 16
Modes “1024×768″
EndSubSection
SubSection “Display”
Depth 24
Modes “1024×768″
EndSubSection
EndSection

Section “ServerLayout”
Identifier “Default Layout”
Screen “Default Screen”
InputDevice “Generic Keyboard”
InputDevice “Configured Mouse”
EndSection

Section “DRI”
Mode 0666
EndSection

That being said, it is very easy to get the HorizSync and VertRefresh for your monitor from it’s manual. Get it, and run “X -configure”, and add the following lines under the “Monitor” section and it should work.

Section Monitor
    # ...
    HorizSync xxx
    VertRefresh yyy
EndSection

There is another way for this — you can download the proprietary binary drivers from ATI I guess.

Check with OpenSuSE forums on this.