AMD/Zen3/Zen2: Altering the Power Limit

[cyring]

Indeed the same limit programmed in BIOS

Stay tuned ...

[cyring]

Released for testings 3dc07cf

[cyring]

• 3950X has an nominal PPT of 142W
• BIOS is programmed with a Power Limit of 156W

• In the Cli or driver argument, we are altering the PL1 to 147W

• Observe the change in the footer:

  1. with all Cores stressed, the Package power consummed raised from 142 to 147 watts
  2. but 3950X is clamped to 150W whatever the applied offset is !

• Remarks:

  1. PL2 is a place holder for the Power Limit set in BIOS. No SMU command specified to alter it.
  2. but PL1 can not be programmed above than PL2

• Code available in the develop branch, feel free to comment.

[cyring]

• Off course, we can also go in the opposite direction.
  Here, applying a negative offset of -50W

1. PL1 is set back to nominal 142W

2. PL1 is now decreased to 92W

Much lower temperature, but also is the all cores frequency.