Recently re-built my system using the same parts as in my old PC, save for a new case.
Started getting random restarts and system black outs (monitor no signal, etc). No apparent reason, PC would just reboot like it had been asked to restart!
Switched to the 'High performance' power plan, and the problems have - seemingly - gone away. Event ID 35 and 41 in Event Viewer are present at or around the time of restarts (obviously at the time of restart for Error 41, and near it for Error 35)
Backing up my theory seems to be that whenever the PC is actually being somewhat used (e.g. photo editing, video work... aka why I'm using Ryzen. Or gaming, for that matter), the rig is. Leave it to its own devices and it will, at some point, auto restart.
This is apparently a problem with the FCU in general, whether the CPU be AMD or Intel made, but interesting that forcing the default Windows HP plan stopped the issue?
Anybody who has noticed this, please let me know as I'd be interested to see if it's a 'just me' thing, or wider spread.