2nd monitor regularly cutting out during full screen games

1st monitor is a old 1080p Dell connected via DP
2nd monitor is a Samsung mu7000, 4k HDR, connected via HDMI
Vid card is Nvidia 2080ti

When playing a full screen HDR game, every 5-15 minutes the 2nd monitor goes black for a second, appears to be switching modes, screen goes very bright for a few seconds, then switches back to normal.

I've swapped cables, changed refresh rates, tried different ports, changed chroma subsampling, borderless windowed. Still reproes.

Only way I've found to stop the issue is to physically disconnect monitor #1. Hoping there's a better way?

Don't know why, but that seems to have fixed it.

Good call!

Ah, the issue popped back up again
@alphanumeric, can you point me to how to setup those shortcuts? Sounds useful.

I have a theory , do you happen to have fluorescent lights home , does this issue happen when someone lights it ?

@nIGHTmAYOR no flourescent lights.

I've connected the 2nd monitor to my 2nd GPU (IGP). The main screen is no longer cutting out, but funny enough, now the 2nd monitor is cutting out with higher frequency, even when not in games.

I previously had the 2nd monitor connected via display port, but had to switch to an old HDMI-to-DVI cable, I think that's what's causing the new issue. I've got a proper DVI cable coming, so we'll see if it still reproes with a better cable.

ok this is starting to sound like a power problem , check for a blown capacitor on the graphic cards / mother board also if possible try to replace power supply unit by another for test and see if this continues .