Fans louder when charging?

Framework Laptop 13 Linux
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[I am using NixOS unstable on a Framework Laptop 13 with an AMD Ryzen AI 7 350 processor. My kernel version is 6.15.5. My BIOS version is 3.03.]

I’m trying to understand what causes CPU temperatures (and thus fan noise) to increase pretty much instantly when I plug in the AC adapter and decrease when I’m running on battery, even after disabling PCIE Dynamic Link Power Management in the BIOS and not using power-profiles-daemon or TLP. Any ideas what else might be reacting to AC adapter events? Or is this just due to the heat generated by the charging process itself?

I don’t necessarily have a problem with it, just trying to understand how this works.

Here’s the output of sudo cpupower frequency-info. Nothing in there seems to change when I plug/unplug the AC adapter.

analyzing CPU 5:
  driver: amd-pstate-epp
  CPUs which run at the same hardware frequency: 5
  CPUs which need to have their frequency coordinated by software: 5
  energy performance preference: balance_performance
  hardware limits: 623 MHz - 3.51 GHz
  available cpufreq governors: performance powersave
  current policy: frequency should be within 623 MHz and 3.51 GHz.
                  The governor "powersave" may decide which speed to use
                  within this range.
  current CPU frequency: 2.45 GHz (asserted by call to kernel)
  boost state support:
    Supported: yes
    Active: yes
  amd-pstate limits:
    Highest Performance: 135. Maximum Frequency: 3.51 GHz.
    Nominal Performance: 77. Nominal Frequency: 2.00 GHz.
    Lowest Non-linear Performance: 24. Lowest Non-linear Frequency: 623 MHz.
    Lowest Performance: 24. Lowest Frequency: 599 MHz.
    Preferred Core Support: 1. Preferred Core Ranking: 135.
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The ec changes the power targets (and profiles) when a charger is plugged in/unplugged. The set peak power is (90% of charger) + 89W which makes boosting a lot more aggressive than the 89W it is set to on battery.

That likely makes this worse as it probably defaults to full-send profile if nothing else is selected, may be worth using one of them.

1 Like
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I personally recommend tuned-ppd, at first (in Fedora 41 era) it was a bit wonky, now it’s mature and saves power on AMD processors

edit: removed incorrect information

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I did not say that, tlp works perfectly fine, no tlp or ppd at all is probably worse than one of them.

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Sorry about the misinterpretion, post edited

Although power conversion loss heats up the computer a little. The main cause is still power management. The same setting in the UI is not the same as the setting to the computer ec. For example in 7840U(sry I don’t have AI 350) performance boosts the instantaneous CPU wattage to 51W on AC but only 41W on battery. Power save caps the sustained load to 25W on AC 15W on bat

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Thanks for the replies. I thought TLP was discouraged for AMD processors (Framework Laptop 13 - ArchWiki). Is that only true for the 7040 series?

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It’s actually a lot worse when looking at the peak power setting (179W vs 89W) you can’t mess with from outside the ec at all as far as I can tell. And even in the lowerst powersave mode it’ll spike there dipping into battery. But of course way too briefly to cause anything fan related.

Annectodaly it works just fine on my 7840u (actually even better than ppd last time I cross tested them but that was alooong time ago) but may as well go with the reccomended thing if you aren’t just being “I’m used to it and it works so I’ll keep using that” like me in this case XD.