I have a secondary monitor, and it is a 19" while the main is 23", and they are both set at 60Hz refresh rate. I've noticed that when I am running certain programs, primarily full screen games or high memory applications (Unreal 4 Editor, as an example), I'll get white, upward scrolling horizontal lines on the second monitor.
The lines can be on the desktop, a browser window, or a full screen video, but the lines are about the same. I also get the lines in the second monitor (and not the main) if I have one of these programs running in the second monitor (if I drag the Unreal Editor to the second screen and have it in focus, for example).
Here is a picture I took of the problem while I had something running on the main and a youtube video going on the second:
Any advice or things to try? Thanks!
The monitors are both running off one GPU: an NVIDIA GTX 970. The main is connected DVI on the monitor side, running to HDMI on the GPU. The second monitor is running VGA on the monitor side, to a DVI adapter on the GPU. They are about 7 inches apart (edge to edge).
Best Answer
My experience is that this could be caused by a few different things.
1: As the comments have mentioned, swapping out cables is the easiest step and could defintely fix the issue. If you don't have extra cables, try just swapping which monitors use which cables, does the problem persist?
2: Interference from some other source could be causing the signal degredation. Make sure the signal cables are separated from any large power cables, and other sources of interference.
3: Play around with the settings, try a different refresh rate, resolution, etc. It might shed some light on the problem or maybe even solve it.