Question Adaptive Sync over DisplayPort 1.4 makes screen black.

Sep 27, 2020
I have a LG 34GN850-B 34 inch monitor that has recently been having some weird issues. I've had a DisplayPort 1.4 cable for a while, and have been able to run Adaptive Sync (G-Sync, as I have an RTX 2070s) and HDR at the same time over it at the DisplayPort 1.4 level. However, currently, attempting to do so leaves the screen completely black. It isn't disconnected, as the display doesn't go idle, it's just black.

I can manage DisplayPort 1.4 with only HDR, instead of HDR and Adaptive Sync, or I can run down to DisplayPort 1.2 with Adaptive Sync but no HDR, but I can't run 1.4, Adaptive Sync, and HDR. It seems Adaptive Sync is the issue (disabling HDR but leaving Adaptive Sync doesn't change anything) but I can't find a fix.

I have tried restarting the monitor, unplugging it and leaving it off for a while before restarting, updating and refreshing the drivers, and I have a new cable on the way, but haven't been able to test it yet. Maybe I damaged my old cable (it was only 3 feet, the new one is 6 feet, and had to be pulled fairly taut to reach), but would this be something that would be typical of cable damage?