With Vega 56, what can you do if you are using OverdriveN and HWinfo64 still reports a higher voltage than was set?
Keep in mind that the set voltage is still a bit dynamic, that's normal and wanted.
Depending on how low you want to go with your voltage you probably need one or both of a) editing reg entries b) flashing to 64 bios.
And don't forget to restart your devices.