Surprisingly, the solution for the first gen Ryzens / 1600AFs is not allowing the power supply idle voltage to go into low power mode. Check your BIOS for it.

Surprisingly, the solution for the first gen Ryzens / 1600AFs is not allowing the power supply idle voltage to go into low power mode. Check your BIOS for it. It turns out many PSUs don't handle low CPU power states well, and disabling C6 just prevents the CPU from being able to idle (and consequently, boost) properly. I've had perfect uptime with my 1600AF in a storage node since discovering this.