Here is a link to Asus Support for the Motherboard B350-Plus : PRIME B350-PLUS Driver & Tools| Motherboards | ASUS USA . They have a very new BIOS update from December 8, 2017. See if this is your correct Asus MoBo and update it. Afterwards see if it made any difference in the Ryzen Power plan. I suspect the newest BIOS is updating to the latest AGESA 1006b which affects the Ryzen CPU operation the motherboard's memory utilization.
Afterwards, try reinstalling the Full set of AMD driver by uninstalling it first using Windows than using DDU to clean any traces of the old AMD driver and software. Before installing the new driver, delete C:\AMD folder in the Root directory and after installing the new AMD driver set.
Be sure you Windows is fully updated via Windows Update before installing the latest AMD Full driver set.
If you still have a problem, try opening a AMD ticket.