One "random" thread suggested to add a ModeLine entry in /etc/X11/xorg.conf file. So I tried. I generated my ModeLine entry using this online calculator: "The XFree86 Modeline Generator: create the mode thats just right for you!"
In the Basic Configuration, I just entered in the resolution of my Laptop LCD, which is "1680x1050" and put in the refresh rate of 60Hz.
Click on "Calculate Modeline", and this will be generated:
So in /etc/X11/xorg.conf, update the "Monitor" section as such:
Section "Monitor"
Identifier "Laptop Monitor"EndSection
Option "DPMS"
# 070809 yky - added modeline:
# http://xtiming.sourceforge.net/cgi-bin/xtiming.pl
Modeline "1680x1050@60" 154.20 1680 1712 2296 2328 1050 1071 1081 1103
You dont need to reboot your computer. You just need to restart X by pressing Ctrl-Alt-Backspace. When you've logged in, you may find X performing better. For example, the tilda application used to be quite jerky as it revealed itself. Now its smooth.
Additionally glxgears used to be a paltry 200-400FPS. Now its an OKay 2000-3000FPS. BZFlag also is now actually playable!
So if you think your X is underperforming, put a ModeLine in and see if theres any difference. Now to figure out why my laptop can't do dual-head/output video.
yk.