I doubt it's the fan. They have a flickering issue. Documented here
https://community.acer.com/en/discussion/573868/x35-flickering-acer-x35-monitor
On youtube as well, though this the Asus pg35vq
https://www.youtube.com/watch?v=BC_...ktz5231srgmokkzinwdrk0h00410.1567359296411269
I have the Asus pg35vq and I have the flickering issue only noticed it in a few games. Battlefield 5 being the worst with the issue.
There was a possibility of a driver fix from Nvidia but that was about 4 drivers ago and it still hasn't been fixed.
Noticed today on my panel that (it appears)one of the fald backlight areas isn't turning on. I've noticed it on white web pages like a light brown spot. When i go to a solid colour page(blue for example)when I hold the cursor over that area its black, when I hold the cursor over any other part of the screen I get a slight halo which is how it should behave. While gaming the area seems to be fine.Also when I first turn it on it seems to be ok.
Overall what with what I've found today, and with the flickering,..god knows.