Alkiviadis Papadopoulos

The Universal x86 Tuning Utility is open source and uses ryzenadj. This is what they seem to do for most mobile APUs: https://github.com/JamesCJ60/Universal-x86-Tuning-Utility/blob/eef398e6e6a42ede887bd511f0a68abda9a823f2/Universal%20x86%20Tuning%20Utility/Views/Pages/CustomPresets.xaml.cs#L1075

Positive values increase core voltage, to use negative values you have to add 0x100000 to them. You can find use cases of undocumented features in the source code of Universal...