CPU usage and core usage strange info

[C0lbyte]

I have a question about some wierd numbers i see. Atleast to me.
In both task manager and HWinfo under total cpu usage its around 0 to 5% in idle and nothing running.
But with all specific core usages there are a few of my P cores that jumps up and down from 15 to 30% constantly.
Why is this happening?

 

[Martin]

Windows has many processes and services running in background performing lots of background tasks...