Resolution/Refresh rate problems (SOLVED)

[Benprofane]

I have googled and searched these forums but I cannot make any progress. I have an ATI 9800 pro and a 19" Viewsonic a90f+. It is capable of 1280x1024 @ 75hz, which is what I would like to run at.

Unfortunately, only 1024x768 and down are available to me. Judging by the flickering screen, I guess I'm at 60hz.

I have looked at xserver.xorg and looked for info on how to configure things, but nothing has penetrated my thick skull so far.

If there is any information you need to provide help, let me know and I'll try to get that posted. Thanks.

[andyvr4]

You need to modify your xorg.conf file in order to allow the higher resolution and refresh rate.

The first step is to backup your xorg.conf file encase something gets broken in the process.

First load a terminal window and type "sudo cp /etc/X11/xorg.conf /etc/X11/xorg.old" You will be prompted for your password. Once you enter it a copy of the original file will be made and you can proceed to modifying the original.

Now type "sudo gedit /etc/X11/xorg.conf", gedit should load with the contents of the xorg.conf file.

Look for something similar to what I've shown below

Section "Screen"
Identifier "Default Screen"
Device "ATI Technologies Inc RV350 AP [Radeon 9600]"
Monitor "Generic Monitor"
Defaultdepth 24
SubSection "Display"
Depth 1
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 4
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 8
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 15
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 16
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
SubSection "Display"
Depth 24
Modes "1280x1024" "1024x768" "800x600" "640x480"
EndSubSection
EndSection

Most likely you will only see the 1024x768 and lower resolutions listed. Assuming that is the case then add the "1280x1024" like what I've shown above. This should fix the lower resolution problem and make 1280x1024 available.


To fix the refresh rate you're going to half to modify a different part of this file. Look for a part that looks like what's below

Section "Monitor"
Identifier "Generic Monitor"
Option "DPMS"
Horizsync 28-51
Vertrefresh 43-60
EndSection

You need to modify the Horizontal resolution and the vertical resolution. The correct values for your monitor can be found by searching the internet for the specs for your monitor as all monitors are a little different. Once you find the correct specs for your monitor enter them in the corresponding spots.

Now save the xorg.conf file and press control-alt-backspace to reset the xserver. When the xserver comes back up you should be able to select 1280x1024 and 75 hz as long as everything went right.

Good luck

[Benprofane]

Brilliant. Thank you very much for the idiot-proof walkthrough. My headache is already going away.

[andyvr4]

Brilliant. Thank you very much for the idiot-proof walkthrough. My headache is already going away.

Great, I'm glad you got everything working .