If you want your video adapter to run at its optimal refresh rate, go to the Registry and look for this string:
Double-click on the 'Refresh' String value in the right pane and change the Value Data to 80 or higher. If the Refresh string does not exist, right-click on the an empty space in the right pane and select 'New->String Value' and name it 'RefreshRate' then click OK. Now right click on it and select 'Modify' and change its value to 80 or higher. Restart your computer for the changes to take effect. If after restarting your computer your screen looks weird, then go back into the Registry and lower the Value string.