I bought a new laptop that I connect to the same external monitor than before, but now I'm noticing something when viewing videos in that monitor. It happens too when scrolling images or with 2D games like MAME.
It's a horizontal line with a bevel in the middle, that is not always at the same height, it moves vertically as shown in the gif linked below
It's a LCD DELL E207WFP connected to the laptop with a HDMI-DVI cable
Graphics card: Intel(R) Iris Xe Graphics (TGL GT2)
GIF (warning: cringey 90s video)
UPDATE:
The integrated laptop screen rate is 60.0 Hz, this may have something to do with the problem. I have tried with the integrated laptop screen on and off
Best Answer
This looks a lot like a common screen tearing artifact. Usually this is fixed by installing proper graphics drivers and then enabling VSYNC on the output. Your video player is likely to have an option for VSYNC and so does MAME.
If the problem persists for the video player, try using
mpvor, if you're on Windows, use MPC.