The 3000 chips do tend to fluctuate. You could try downloading and installing the latest AMD B450 chipset drivers then using the AMD Ryzen Balanced or High Performance Windows power plans to see if it is an issue with C-State or P-State voltage/frequency management. I'd also use HWiNFO64 to montitor what your Core Voltage is doing, my 3700X is doing 33c/43c/35c (Min/Max/Av) with Core Volts 0.99v/1.49v/1.10v (Min/Max/Av) on the AMD Ryzen Balanced power plan, the High Performance plan is doing 33c/50c/38c with Core Volts 1.01v/1.49v/1.28v.
Hope that helps.
mine dose the same on HW it shows its pined at 4.3 with the volts pined at 1.333 and when idel when i run CB20 the volts go to 1.28 but Ryzen Master shows the cores go down to around 300 to 900 and volts at 1.09 idelOK. I laready have latest chipset and am using the Ryzen 'balanced' power plan.
Strangely Ryzen Master seems to report the CPU downclocking to around 2000MHz however HWiNFO suggests all the cores are basically pinned at 4300.
Idle voltage tends to be around 1.4V-1.45V it looks like
the think is i dont run them at the same time and out of all 3 ryzan master comes closest to what i hope is correct only thing i think ryzan master is getting wrong is the peak volts it shows at 1.333Looks like there can be issues with reporting if you are using Ryzen Master along with HWInfo which you both are. Try installing the latest version of HWInfo (v6.24) - https://www.hwinfo.com/download/ - Personally I don't use Ryzen Master, it has been more of a problem than a help, it doesn't do anything that you can't do in BIOS and I find HWInfo much more useful for monitoring, so my advice would be to stop using it.
BTW - the words you meant to use were does, pinned & idle.