Guys. few posts back you will see

SOME TUTORIAL ABOUT AGGRESIVE UNDERVOLTING.

I suggest looking at it

and also:

New OS image
If you have newer Nvidia GPUs you can reflash your rig with that image but if it is working fine then it is no need to reflash
- newest kernel 4.17.14
- newest amd driver 18.20
- newest nvidia driver 396.51
- image is available for RX/NV in the About OS menu
- drivers are never updated in auto-updates becasue it would broke your rig ofcourse.