I'm running a single 3440x1440 monitor with a stock clock Powercolor 5700XT Red Devil & I've been getting random black screens ever since I bought it, I could go days or weeks without a black screen but last week it did a black screen & died permanently, When I tried to boot up I got nothing on screen, no spinning fans & no lighting up except for a red light on the pcb near where the monitor cables plug in, I still have an RX 480 Red Devil so I did all the checks like reseating the gpu, testing the power cables et cetera with both cards & the 480 was fine so I returned the 5700 to get it fixed under warranty.
Feels like its getting worse to be honest went turn PC on today and bios screen windows loadings show but once get to login both screens go off.. had turn on and off a few times to get woeking and now keep getting crashing again only other thing i had repair a core windows file other day maybe just maybe a fresh install of windows might or i am using a PCI riser cable but was fine for a month or so very few if no crasheshmm. If not card is dying and i have no warranty from the looks of it since i waterblocked it a week or so after i had it:'( if 2 months old
I had this exact same issue (black screen, audio, need to power cycle) with a much older AMD card and would get different periods of "OK" with much older drivers but it was never 100% and oddly I think was linked to specific game engines.
As they tasked the system more I assume the power needs of the card ramped up, fans came on and chips got hot and my system couldn't cope.
I assumed that different (older) drivers had different power management settings and were just more stable.
Whereas newer drivers push for every bit of performance and use more power.
I tracked the problem down to an old power supply that was working "fine" most of the time. Replaced it and updated drivers to latest ones and had no more problems.
PSU is a few months old and was working fine with my AMD fury which was more power hungry then this this has black screened even on desktop when card is idle