Undervolting a Ryzen 5 2400G

tjknejrnbtkjw4bk5jbwkejb · December 3, 2019

I have a Ryzen 5 2400G system with an ASRock B450M Pro4 motherboard and no graphics card. I started undervolting the processor a long time ago with 1.25V (stable), I'd like now to undervolt more, but I have a problem now: I have seen this thread on Level1Techs forums, I have tried ZenStates, tried setting a voltage of 1.225V and 1.2V, the voltages have listed correctly, but according to zenpower, the core voltage still goes up to 1.25V. I also tried setting the voltage from the BIOS, but it still went to 1.25V (and again ZenStates shows the voltage I set).

To provide as much information as possible, here's how I tried to set the voltage in the BIOS:

I set "CPU Frequency and Voltage Change" (or similar, I took that term from the manual) to manual and set the voltage to 1.225 and frequency to 3600 (didn't change it). I saved the settings and booted.

The command with which I set the core voltage to 1.225V with ZenStates (the number sign indicating that the command was run as root):

# python zenstates.py -p 0 -d 8 -f 90 -v 34

And the ZenStates output after both BIOS and ZenStates undervolt attempt:

# python zenstates.py -l
P0 - Enabled - FID = 90 - DID = 8 - VID = 34 - Ratio = 36.00 - vCore = 1.22500
P1 - Enabled - FID = 8A - DID = C - VID = 5C - Ratio = 23.00 - vCore = 0.97500
P2 - Enabled - FID = 80 - DID = 10 - VID = 6C - Ratio = 16.00 - vCore = 0.87500
P3 - Disabled
P4 - Disabled
P5 - Disabled
P6 - Disabled
P7 - Disabled
C6 State - Package - Enabled
C6 State - Core - Disabled

I have BIOS version P3.30.

The manual of the motherboard.

What could be the problem? Am I doing something wrongly?

(As a side question: assuming an average result from the silicon lottery, who far can I expect to be able to undervolt the processor?)

(I'm really sorry if I'm missing something (obvious). I'm also really sorry if I at some point stop answering. It probably means that I have found the solution and it was something too embarrassing. If I do find the solution on my own, I'll try to tell it, but I can't promise anything (sorry))