I bought this card brand new yesterday. I've DDU'd, kept everything at stock, and I'm crashing in multiple games within a few minutes of launching them. I can watch everything with the Radeon Overlay and the temps stay below 65, GPU utilization never maxes out, everything looks fine. Then the system shuts down and reboots. No BSOD, no warning, just shuts down. I'm at a loss here and I really don't want to return it already but I'm leaning that way.
Main drive is a Muskin 500GB SSD
Ryzen 1600 @ 3.7
MSI RX Vega 56 8GB OC edition
Check your power supply first, that card requires a minimum of 650w.
When a shutdown occurs like that it usually means a safety has been tripped on the power supply or the motherboard.
Do you have both power cables plugged into the card? (Using two separate cables from the power supply)
I'll add that I have an HX750.
I returned the MSI card and got an ASUS STRIX 56, but still have the same issue.
So far I'm having much of the same issues as the guys in this thread RX Vega64 Liquid -- Possible HBM2 Downclocking / Upclocking / Black-Screen issue
Although locking memory to one state doesn't completely stop games from crashing, only causes fewer.
In this case I believe your PSU is mostly at fault, you want something with only a single 12V rail, 650W and 80-gold or higher. Did you end up fixing the issue or was your card returned?