Tips & Tricks

The fix presented below includes only editing of Windows registry, hence no need to run any third party apps of unknown origin.

Theoretically this fix should be display-driver/adapter independent since it modifies settings for the monitor rather than display-driver/adapter itself.

IMPORTANT:
Before making any changes make sure that your monitor supports the refresh-rate-resolution combinations you wish to use. Use this fix at YOUR OWN RISK.

Assuming that you have installed your monitor correctly (the monitor driver supports the desired vertical refresh rate, in our case 75 Hz), and you have a "normal" system (no multi-monitor support enabled, etc.) do the following:

Open regedit and find this key:

[HKEY_LOCAL_MACHINE\\system\\CurentControlSet\\Control\\Class]. Expand the "class key"; you will see a bunch of keys similar to

{1113E534-EAF87542.....}

If you select one of them you'll see some values. There should be a string called "Default" or "Class" or both of them, identifying the kind of device it is, like "Modem", "Keyboards", etc. Find the key that has the string value "Class"="Monitor".

Expand that key and there should be at least one key, typically "0000". There might be more; in that case, you'll have to see which one is currently in use. Just modify them one by one.

Start by expanding the "0000" key; there should be a key "MODES", expand it, now you should see a key with your monitor's max resolution. Now, suppose that you want a 75 Hz vertical refresh rate in resolution 1024x768. Add a key in "MODES" called "1024,768". In the "1024,768" key, add the String value

"Mode1"="75-75,75-75".

Now if you open "Display properties" (right-click on your desktop) click the "Advanced" button and go to the "Monitor" tab, you will be able to select only one refresh rate, namely 75 Hz. Provided, of course, that the "0000" key was the key currently in use and that the "Hide all unsupported modes" checkbox was ticked. Repeat the procedure for all refresh-rate/resolution combinations you wish to use.

Go to "Display properties -> Advanced -> Monitor" and select the refresh rate, here 75 Hz.
Basically what this fix does is setting the lowest refresh rate supported by your monitor to the one you wish to use. Now all games should run on the specified refresh rate regardless of whether they use Direct3D or OpenGL.

This fix should work in Windows XP too.

Source: NT Compatible