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Reducing Display Monitor Flicker

THIS DOCUMENT DOES NOT REPRESENT A POSITION OF SEATTLE COMMUNITY NETWORK. This is personal opinion of the author, and SCN doesn't even take a position as to its accuracy! The official SCN help page is linked above.

EXPLANATION

skip to the instructions

Monitor flicker particularly affects people in the autism spectrum including people with Asperger's Syndrome. Monitor flicker can also provoke migraines.

Humans can perceive lights flickering up to 25 Hz. Even though not perceptible, flicker at much higher frequencies affects people by causing eyestrain. Many people find fluorescent lighting to cause eyestrain, although fluorescent lights flicker at 120 Hz in North America (100 Hz in countries with 50 Hz power). Continuous work behind a monitor running at 60 Hz will be particularly stressful for someone with Asperger's Syndrome. (So why does Bill Gates refer to his high end operating system as "NT"?)

Flat panel displays are not significantly affected by this.

Screen flicker is most obvious when viewed from a distance, with fluorescent lighting in the room.

This is Windows oriented. Linux normally uses optimum settings for monitors.

Windows normally will identify the monitor as a "Standard SVGA Monitor". The default drive speed for a "Standard SVGA Monitor" is approximately 60 Hz. (Setting drive speed to "optimum" may increase this slightly; and perhaps up to 75 Hz.). The "Standard SVGA Monitor" default will normally occur even with factory "package configuration" computers, since monitor selection is still a Windows function.

Many "plug and play" monitors do provide information which is recognized by Windows. Sometimes the type of monitor isn't indicated in the settings, but the refresh rate options (e.g., 85 Hz) are given in the "Adaptor" settings. So..

If you can select a refresh rate of at least 75 Hz, you almostly certainly have a monitor defined by Windows. The "refresh rate" is found in display properties --> <settings> --> <advanced> --> <adapter> --> <refresh rate>

The monitor selection is normally just an .inf file which identifies the refresh rates of one or more monitors. It is not a true software device driver. The device driver is associated with the video card. The video card device driver software uses the monitor's .inf information to offer you the different drive speeds.

So the purpose of this page is to attempt to upgrade the settings so as to run the monitor at higher speed.

Windows will normally correctly identify the video card inside the computer.

NOTE: This only works for SVGA monitors. All modern monitors are SVGA. (The old VGA monitors from the early '90s typically only go up to 60Hz.)



WHAT TO DO IF YOU MESS-UP

Restart the computer and run in "Safe Mode" (W98) or "VGA Mode" (NT). Then reduce the monitor frequency and try again. If you pay attention to the screen prompts, this shouldn't be a problem, because Windows will request a confirmation of the change. But I've done it wrong a couple of times!

If your monitor ever blanks out when you try to adjust the frequencies, just don't touch anything and wait 15 seconds patiently. The screen should return to its previous state again. This means the setting you selected is not compatible with the monitor and you shouldn't use it.

"INSTALL" THE MONITOR

CHECK WHAT YOU HAVE

Look at display properties to see if the monitor is already identified:

  1. RIGHT click on the desktop background ("white space"). Select <properties>.
  2. <settings> - On Windows98 and later the display type and video card should appear on that window. If not continue..
  3. click <advanced>.
  4. Look under <monitor> and <adaptor> to see that the monitor is correctly identified. The <adaptor> window should have a selection box which allows selection of different monitor speeds. (A custom installation may have a different monitor defined; this may be okay. Some also say "Standard Plug-and-Play" even if they define a proper set of refresh rates.)

If the monitor is already "installed", then select a high refresh rate and enjoy!

IF YOU HAVE A COMPUTER PERSON WHO CAN DO IT

Okay, the display says "Standard VGA". You work for a business or other entity which has an on-site MIS department. Just ask that they "load the monitor driver information files" for the monitor, and that you want that so that you can "set the monitor to its highest refresh rate."

GET THE DRIVER

  1. Look for the model designation of the monitor. If you have a newer monitor or are running Windows 95, go onto the net and find "[brandname] Display Driver". Download it.
  2. Open the downloaded file in a logical place such as \windows\system\drivers\monitor\sony. (Make a directory for this.) If the file is brandname.inf, just place that file in the selected directory.
  3. While you're at it, go to the "my computer" or "explorer" and change the properties of the \windows\inf\ folder so that it is NOT hidden. It's difficult to browse for an .inf file in that directory if the directory is hidden!


INSTALL THE DRIVER

  1. RIGHT click on the desktop background ("white space"). Select <properties>.
  2. <settings> - On Windows98 and later the display type and video card should appear on that window. If not continue..
  3. Click <advanced>.
  4. Click on <monitor>.
  5. Click <change>.
  6. Proceed to driver selection.
  7. Select "have disk".
  8. Browse until you get to the location of the .inf file that you've downloaded. Usually the file name will appear in the box when you've gotten to the right place.
  9. Select that file.
  10. Identify the monitor if there is a choice.
  11. When the file is installed, go back to the <adaptor> setting above and change the drive rate.
  12. Enjoy!


SOMETIMES THE NEW DRIVER WON'T INSTALL

  1. In "Control Panel" find "System"
  2. Select <Device Manager>
  3. Expand <monitors> by clicking on the "+".
  4. Select the "standard monitor" you want to change.
  5. Click <remove>.
  6. Restart computer. Windows should identify "new hardware" and let you "install" the correct monitor.
  7. Select that file.
  8. Identify the monitor if there is a choice.
  9. When the file is installed, go back to the <adaptor> setting above and change the drive rate.
  10. Enjoy!


PROBLEMS

Image Bad or No Image
Go to a slower rate and try again. If necessary start in "Safe Mode" or "VGA Mode".
If your monitor ever blanks out when you try to adjust the frequencies, just don't touch anything and wait 15 seconds patiently. The screen should return to its previous state again. This means the setting you selected is not compatible with the monitor and you shouldn't use it.
Program Crashes related to Graphics Driver
Sometimes this can be caused by full "hardware acceleration". This is in the monitor "performance settings":
  1. RIGHT click on the desktop background ("white space"). Select <properties>.
  2. <settings>
  3. click <advanced>.
  4. Look under <performance> and select "none" for "hardware acceleration.". If that fixes the problem, try intermediate "hardware acceleration" settings to see if they work. This is a known bug with WordPerfect for Windows.
A program immediately crashes with the faster settings.
Try the program at the slower video speed, and then go back to the higher speed. Sort of black magic but it does work!
Other "fatal error" program crashes related to video.
Write down the name of the module and go out on the net and see if someone somewhere addressed the issue. If not in your program, it may appear in something else.



ALTERNATE APPROACH - GENERIC MONITOR SETTINGS

Here is another approach, from Eric Chen Yixiong, explaining how to obtain higher refresh rates on a "generic" monitor.

Date: 5/1/01 5:09 AM
From: Chen Yixiong, Eric
Subject: Minimising screen flicker

I noticed some of you here may want to minimise screen flicker. I can actually see the monitor flicker at 60Hz and even a little at 72Hz. If you want to reduce eyestrain or stress (I read that flickers can affect AC behaviour), then you can either get an LCD screen or change your monitor refresh rate.

Warning: The method may damage your monitor in some special cases (though it never happened to me), try it at YOUR OWN RISK and with computer competent people to help you!

Before doing it, please ensure your monitor is not VGA but SVGA or better. SVGA monitors usually cannot support refresh rates higher than 60Hz. Generally, those newer monitors from 1995 onwards are all SVGA.
  1. If you use Win95 or Win98, go to Start Menu, select Control Panel and then Display. In Display, go to Settings and click Advanced. Select the section "Adapter". You should see an option called "Refresh Rate". Click on it.
  2. If you see a list of frequencies, skip to Step 4. If you don't see any numbers (but just "Default" and "Optimum"), go to section "Monitor". Make sure your monitor or display card doesn't have special drivers (like some Voodoo 3 cards) that you may accidently interfere with if you change your settings.
  3. Click on "change", click "Next", then select "Display a list of all drivers..." and either select the "Super VGA 1028X768 @ 75Hz" monitor (if you had Win98, which saves you the trouble of the step 4) or the Acer 78i (which usually works). Click "Next" until you get to "Finish". After you changed your monitor, you should see that the Refresh Rate option shows you the list of frequencies.
  4. Go to the "Adapter" section with the "Refresh Rate" option. To start testing, you should start from 72Hz and click Apply. If your monitor can work properly then you can try 75Hz. Generally the larger the number the better but some monitors may get damaged more easily if you set the refresh rate too high, so try anything above 85Hz and at your own risk.
  5. If your monitor ever blanks out when you tried to adjust the frequencies, just don't touch anything and wait 15 seconds patiently. The screen should return to its previous state again. This means the setting you selected is not compatible with the monitor and you shouldn't use it.
As for other systems other than Win2k, sorry, I do not use them and thus I cannot provide advise.



WHY DOES THIS AFFECT PEOPLE WITH ASPERGER'S SYNDROME?

I don't know.

Normally the monitor settings are just left alone. People with Asperger's Syndrome tend to be particularly sensitive to video flicker, and so flicker is an issue for people with Asperger's Syndrome. That's why I posted this.

Asperger's Syndrome (AS) is the same as or similar to high functioning autism (HFA) and results in a person being object-focused rather than person-focused. An "Aspie" will not easily follow body language in conversation. Occasionally AS people have particular intellectual "special interests". Famous people who have been described as having AS characteristics include Albert Einstein, Vincent VanGogh, Leonardo daVinci and Temple Grandin. Bill Gates and Al Gore have also been described in this manner but have not self-identified as Aspies.

Much more detail can be found from the following link sites:

www.autism.org Center for the Study of Autism - incl. articles by TG
Ooops... Wrong Planet! Syndrome - Autism Spectrum Resources
The Experts - from Wrong Planet, First and Second Hand Accounts of Life on the Autism Spectrum
autistics.org: resources by and for persons on the autistic spectrum
Institute for the Study of the Neurologically Typical
Autism Links
nw autism/as support & social groups
Autism and Relationships pages at SCN
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'Microsoft', 'Windows95' and 'Windows98' are trademarks of a large company in the suburbs of Seattle.

Stan P.
Comments about this site: email me

http://www.scn.org/~bk269/
first written May-01; last revised 07 Sep 02

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