Changing screen resolution in Xorg.conf

My screen with a resolution of 1240x1024 wasn't accurately displayed by Xandros desktop 4.1. The fonts were looking fuzzy and were barely readable.
How to solve:

Backup Xorg.conf file:

sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf_backup

Go to folder and file with root privileges for example in Ubuntu:

sudo gedit /etc/X11/xorg.conf

Open file by clicking and look for Section Screen and ad a line like:

Modes "1240x1024_60.00"

Look at the way it's defined in the existing xorg file; it may be a bit different according to your distro.

This also can be of importance by lacking performance of your monitor:

How to edit or add HorizSync and VertRefresh lines
Find your monitors manual (manufacturers website and Google are useful).
Look for hozizontal sync and vertical refresh rates, also if bandwidth or maximum dot clock / pixel clock is mentioned, write it down.

Edit xorg.conf and put correct values to your xconf.org's Monitor section. Something like this:

Code:

Section "Monitor"
  Identifier    "CM752ET"
  HorizSync     31-101
  VertRefresh    60-160
EndSection

By changing this to a broad range your monitor will likely fit into it.
Source: http://ubuntuforums.org/showthread.php?t=83973