This cvar is currently bugged. The only in-game setting you can use is 60Hz.
You generally don't wish to change this setting as wow will usually auto-detect this correctly (bug not-withstanding).
- 60 (Hz)
- Most LCD Monitors
- 75 (Hz)
- Most CRT Monitors
- 120 (Hz)
- Special gaming monitors - in WoW, these are meant for use with the Nvidia 3D goggles.
Changing this setting
In-game, type the following
/console gxRefresh setting
Alternatively, you can exit wow, open the Config.wtf file, and add the following line:
SET gxRefresh setting
Fix for current issue
When wow loads, it'll automatically reset gxRefresh back to 60Hz. However, to get around this you can edit your Config.wtf file to 75/120, save it, then set the file to read-only.
Please note that setting this file to read-only will keep wow from saving any engine, graphics or sound changes.