Have a look in Task Manager Processes, see if/what is using it. Or any Startup apps.?
What Windows power plan, any OC?
Mine is usually 1-5% on balanced power plan,
![5600x idle.png 5600x idle.png](/t5/image/serverpage/image-id/100211i5CBF0D58DE7AC8F9/image-size/large?v=v2&px=999)
My PC- Ryzen 5 5600x, B550 aorus pro ac, Hyper 212 black, 2 x 16gb F4-3600c16dgtzn kit, NM790 2TB, Nitro+RX6900XT, RM850, Win.10 Pro., LC27G55T.