Problems with monitor KG271C

Gamborg

I have acquired an Acer KG271C 1080p 144hz monitor.

It is difficult to describe the issue. When I'm specifically playing games in "windowed full-screen", it seems the brightness is fluctuating very quickly, it is very noticeable at the edges of the screen.
I had this issue with my previous screen as well before i returned it thinking it was faulty(although it was, since it had a dead green sub pixel as well(AOC not Acer)).
I've tried troubleshooting this myself using google, but not knowing what to call this, it became very difficult. First i thought to call it "flickering", but that's something very different than whats happening with me. I've tried recording it with mobile, but the mobile hardly catches this brightness fluctuation. Hoping someone could help me in here, it is very disruptive for the eyes.
This was not an issue with my old broken 60hz 1080p monitor, only started when i tried buying a 144hz 1080p monitor. I tried setting the monitor to 60hz, but the problem persists.

billsey

What are you connecting to the monitor and which port are you using? It could be anything from a funky cable or power supply to a hardware issue with the monitor itself. Since it's happened with two different monitors, I'd lean toward the cable or video source.