I think what you are experiencing here is power saving which is a good thing when you processor is idleing as it reduces your computer power consuption and so your electricity bill as well!
Download a CPU stress test software like Prime95, run it and check how your CPU frequency and voltage reacts when it's under 100% load.
On my computer when it's idling this is the voltage and the frequency of my processor (thanks to intel speedstep, but there must be a similar thing for AMD processors):
And here is the resulting power consumption of my computer (from a smart plug which my computer is plugged into, i apologize for my baguette language :) :
When i stress test my CPU this happens:
So you can see that power saving is a good thing, otherwise your computer would eat watt all the time and your electricity bill would go to the roof ;) Also almost all power consumed by a computer is transformed into heat which goes into your room so in summer you want to avoid that :)
post edited by Neutro - 2018/08/14 05:27:56