I'm a competitive CS player that enjoys playing 4:3 resolutions. The problem comes when I try to play 1280x960 black bars (maintain aspect ratio), It will not allow this resolution on 144hz or 120hz options. Anything lower than that and it works fine.
Here's a list of resolutions that do NOT work with 144hz and Maintain aspect ratio option: 1280x768(16:10), 1280x960, 1280x1024, 1360x1024, 1400x1050, 1600x900(16;9) and 1680x1050 (16:10)
Some resolutions that work fine with all hz: 1920x1080, 1366x768, 1024x768, 800x600
Can you guess what problem is?