Persuading Ubuntu to use 1024x768 at 100Hz

Andrew virgule88 at
Tue Jul 26 01:59:09 UTC 2005

On Monday 25 July 2005 20:00, Michael Wardle wrote:
> On Tue, 2005-07-26 at 01:37 +0200, Gábor Iglói wrote:
> > The matter is that I can only get 1024x768 at 85Hz while the monitor is
> > capable of 100Hz.
> I just had a look at the Screen Resolution control panel, and mine only
> allows selecting of 60, 75, and 85 Hz.  These look like the predefined
> VESA modelines.
> If these aren't satisfactory, try adding your own modelines to
> xorg.conf.  There's a couple of web sites out there to help calculate
> the numbers.  You might also be able to use a configuration tool such as
> xvidtune.

'gtf' does just that. It generate a Modeline out of the fed parameters. Its 
part of xserver-xorg package so you already have it installed.
For 1024x768 @100 Hz:

gtf 1024 768 100

Paste the output in /etc/X11/xorg.conf "Section "Monitor"" directly below 
"VertRefresh     xx-yy" and above "EndSection" While you are in xorg.conf, 
doublecheck the HorizSync and VertRefresh values to make sure they matches 
those found on the back of the monitor or in it's manual.

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