Ryzen-5800x3d-linux-undervolting

A Python script to use Ryzen SMU for Linux PBO tuning of Ryzen 5800x3d CPU. Mostly needed for Ryzen 5800x3d undervolting.

What is it ?

This is a linux implementation of the PBO2 undevolting tool used to undervolt Ryzen CPUs in Windows. More info on how to do it in Windows is here: https://github.com/PrimeO7/How-to-undervolt-AMD-RYZEN-5800X3D-Guide-with-PBO2-Tuner

How to use it ?

1. Clone this repository: https://github.com/leogx9r/ryzen_smu and install the Ryzen SMU driver that makes comunication with Ryzen SMU (System Management Unit) possible

git clone https://github.com/leogx9r/ryzen_smu
cd ryzen_smu
sudo make dkms-install

Now make a reboot. The dkms-install should make a new module into you system called "ryzen_smu". It will autostart next time you reboot your system. Without it the provided Python script will not function.

2. When you have the driver installed and functioning clone this repository and start the undervolting tool.

git clone https://github.com/svenlange2/Ryzen-5800x3d-linux-undervolting.git
cd Ryzen-5800x3d-linux-undervolting
sudo python3 ruv.py

You should see this output:

usage: ruv.py [-h] [-l] [-o OFFSET] [-c CORECOUNT] [-r]

PBO undervolt for Ryzen 5800X3D processor

optional arguments:
  -h, --help            show this help message and exit
  -l, --list            List curve offsets
  -o OFFSET, --offset OFFSET
                        Set curve offset
  -c CORECOUNT, --corecount CORECOUNT
                        Set offset to cores [0..corecount]
  -r, --reset           Reset offsets to 0  

3. The tool gives you ability to see and write the PBO curve offsets on the fly. The corecount enables writing the offset to all the hardware cpu cores. On 5800x3d you have 8 cores (other 8 are virtual hyperthreading counterparts). So in my case Ill use it like this:

sudo python3 ruv.py -c 8 -o -30
Core 0 set to: -30 readback:-30
Core 1 set to: -30 readback:-30
Core 2 set to: -30 readback:-30
Core 3 set to: -30 readback:-30
Core 4 set to: -30 readback:-30
Core 5 set to: -30 readback:-30
Core 6 set to: -30 readback:-30
Core 7 set to: -30 readback:-30

The "readback" in the response indicates what value was stored in the registers. I found out that if ill try to push it further than -30 it will allways read back -30 so there is a hardware limit to the number. All offsets will reset on reboot so install this commanline as a service to automate things at reboots. The offsets need to be negative as we want to undervolt the CPU.