Comment by raisin_churn

You want to check out CoreCtrl[0] for GPU undervolting. I'm not sure exactly what features are available for RDNA1-3, I remember reading an issue that some level of control was lost at some point, but granular clock/voltage control, fan curves, etc were all available for my Vega 56.

[0] https://gitlab.com/corectrl/corectrl