The motherboard is an Asus Prime X370-Pro. The cores boost to around 4.2 GHz during a Cinebench multi-core test.
What are the temps and core voltage?
I found on my Asus CH6 x370 board that the voltage was actually already low and mine would only boost to about 3.6GHz all core, the temps were great though, I ended up adding a little core voltage, setting SOC to 1v and I could get to 4.45GHz all core.
I see lots of people reducing voltage but you need to check what yours is doing before either removing or adding voltage.
Here are the settings I settled on to get nice and stable, I am running on AIO water cooling.
* SOC voltage 1.00
* BCLK Freq 101
* FCLK Freq 1800 (im running 3600 memory)
* Core Performance Boost enabled
* CPU Core Voltage offset mode
CPU Offset Mode Sign +
CPU Core Voltage Offset
+0.01250
Advanced/ AMD CBS/ NBIO Common/ XFR Enhancement
* Precision Boost Overdrive manual (can try on auto but for me this worked better)
PPT 100
TDC 70
EDC 100
* Precision Boost Overdrive Scalar manual 5X