I have these very faint (watermark-like) ~3 px wide horizontal lines across the whole monitor that move upward. If i set the refresh rate to 59 Hz the lines move very fast, instead at 60 Hz they're much much slower.
Monitor: Dell u2412m
GPU: Nvidia GTX 760
MOBO: ASUS z87 Deluxe
CPU: Intel 4770K
Unsuccesful things i've tried:
- Unplugged everything unnecessary: only power cord, mouse, keyboard, monitor.
- Turned off nearby Wi-Fi router.
- Switched from HDMI -> DVI cable to DisplayPort -> DisplayPort cable.
- Disabled any kind of overclocking.
- Moved GPU to another PCI slot.
- Totally removed the GTX 760 and tried the integrated Intel HD 4600 (DisplayPort -> DisplayPort).
- Checked if BIOS is affected: it is (59hz).
- Plugged PC and Monitor to a normal power strip instead of my UPS.
- Plugged monitor to my laptop (HDMI -> DVI): this made the lines disappear both at 59hz and 60hz.
I'm definitely out of ideas here.
Edit: another thing i've tried (to rule out my electrical system) is to unplug the power cord from the wall outlet and let the UPS kick in. The lines still remain though.