Give my suggestion a go.thanks for responding matt yea rdping from my desktop to a laptop in the same house (laptop has crap resolution and rdp will use the monitor res, also lack room for the laptop in my desktop setup - works really well actually)
but whilst RDP is active the main pc is idle, since the laptop does all the grunt work. I've noticed it happened yesterday with rdp too and the day before, but ive also noticed it happened when i was on the desktop too. this was all with gen 4 and resize bar enabled (already tested disabling resize bar and it still crashed).
doesnt appear to happen in game at all.
tried it doesn't make any difference, only thing that appears to help is setting pci gen 3 specifically. (no random reboot since swapping from gen 4 to 3 thus far).
sorry forgot to mention I'm on 21.1.1 too and chipset drivers 2.10.13.408. (both latest)
edit what feels like 500.. also got 2 gen 3 nvme drives.
Be interested to see if anyone else has the same issue, and if your workaround fixes it.
Idle restarts can also be caused by overly aggressive curve optimizer settings but you have a 3900X so that does not apply to you.