Choose the resolution YOU want in xorg.conf

Xorg has been recently updated to 7.3 and apparently uses xrandr to set the best resolution for you.
It works well in most cases, but sometimes, you'll want to set X to start in a resolution YOU choose.
Of course, the first thing you do is to tweak your xorg.conf as you did it for about x years now and happily press [CTRL][ALT][<--] and ..? wtf o_O the resolution has not changed. After having checked twice your xorg.conf, you're still stucked in that resolution and your desktop is unusable due to all icons in your gnome-panel that are not visible anymore... So, how to modify xorg.conf to your needs? Here is it! Say you want a resolution set to 1600x1200 at 75Hz, you use gtf tool to output a Modeline that'll be used in xorg later:

$ gtf 1600 1200 75

# 1600x1200 @ 75.00 Hz (GTF) hsync: 93.97 kHz; pclk: 205.99 MHz
Modeline "1600x1200_75.00" 205.99 1600 1720 1896 2192 1200 1201 1204 1253 -HSync +Vsync

Now, open your xorg.conf, then find Section "Monitor" then add those two lines as in the following -example- code:

Section "Monitor"
Identifier "Configured Monitor"
Modeline "1600x1200_75.00" 205.99 1600 1720 1896 2192 1200 1201 1204 1253 -HSync +Vsync
Option "PreferredMode" "1600x1200_75.00"
EndSection

Then, find Section "Screen" and add this example code:

Section "Screen"
Identifier "Default Screen"
Monitor "Configured Monitor"
DefaultDepth 24
SubSection "Display"
Depth 24
Modes "1600x1200_75.00"
EndSubSection
EndSection

Be sure that Modes string is the same as above!

... And that's all? I hope so, let's save this file and restart your X server.

Original article was posted here