I would say you need to look at any Apps. set to start on login, many 3rd party (and motherboard Apps.) can have excessive use of cpu.
The minimum frequency variation is usually not an issue (depending on monitoring App. (and its poll rate ?)).
And of course, have you asked on either asus or OC forums for optimal non OC bios settings for your cpu/mobo combo.
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..