I have a 60Hz monitor with a native resolution of 1980 x 1080, so in Windows I have my resolution/refresh rate set to 1920×1080/60Hz as expected, but if you go to 'Display Adapter Properties' and then 'List All Modes', there are a wide range of resolutions and refresh rate combinations to choose from.
My question is, what happens if I set it to 1920×1080/30Hz? I understand the resolution part because that's being drawn in the computer so I can understand how Windows is able to control that, but the refresh rate is a property of the monitor, so if I set it to 30Hz, does Windows (or any OS for that matter) somehow communicate with the monitor and tell it to run at 30Hz?
I'm aware of EDID which monitors use to tell the OS what it is capable of displaying, is it anything related to that?
Best Answer
Does Windows (or any OS for that matter) communicate with the monitor and tell it to run at 30Hz?
The graphics card controls the refresh rate, and can overide EDID if instructed to do so.
Normally the settings in the graphics card's control panel are used select a particular refresh rate at any resolution as long as it's supported by both the graphics card and monitor.
If you select a higher refresh rate than those supported by the monitor then an 'Out of Frequency' error occurs resulting in a blank screen.
There are programs that can define custom resolutions/refresh rates. See Custom Resolution Utility (CRU) for one such program.