On SuSE, I've had problems in the past with video sizing problems which was fixed after installing the propriety nvidia driver and running SaX2. The most recent Xorg server can calculate settings on its own without an xorg.conf file. However if your monitor does't communicate it's capabilities properly, you may need to create an xorg.conf file.
If you are using the nvidia driver, you could run the "nvidia-settings" program to generate one. Then run the nvidia-xconfig program to fine tune it.
Last edited by jschiwal; 02-02-2010 at 02:41 AM.