I found a manual workaround that restores expected performance on this boot.
The CPU had:
- /sys/devices/system/cpu/intel_pstate/no_turbo = 1
- /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost = 0
- cpu0 scaling_max_freq = 2200000
I manually changed the values to:
- echo 0 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
- echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost
After that:
- no_turbo = 0
- scaling_max_freq increased to 5600000
- powerprofilesctl changed from degraded yes to degraded no
- the GNOME power warning disappeared
- the fans ramped more normally
- my pytest suite completed about 3 minutes faster
than my less powerful Dell Ubuntu laptop
So the performance issue is resolved on the current
boot with a manual workaround.

The issue is reproducible across reboot and is not resolved permanently.

After reboot, the system again reports degraded performance and becomes
visibly slow. The following values returned after reboot:

- /sys/devices/system/cpu/intel_pstate/no_turbo = 1
- /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost = 0
- cpu0 scaling_max_freq = 2200000
- cpu0 base_frequency = 2200000

So after reboot the CPU is again capped at the non-turbo/base frequency
range.

At the same time, powerprofilesctl again reports:
performance -> Degraded: yes (high-operating-temperature)

Manual workaround still restores normal behavior for the current session:
echo 0 | sudo tee /sys/devices/system/cpu/intel_pstate/no_turbo
echo 1 | sudo tee /sys/devices/system/cpu/intel_pstate/hwp_dynamic_boost

After applying that:
- no_turbo becomes 0
- scaling_max_freq returns to the turbo range
- powerprofilesctl changes to "Degraded: no"
- the GNOME overheat/performance warning disappears
- fans ramp more normally
- performance returns to expected levels

This suggests the issue is reproducible on boot and that some boot-time
firmware/kernel/userspace interaction is incorrectly restoring
no_turbo=1.

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https://bugs.launchpad.net/bugs/2148099

Title:
  power-profiles-daemon reports high-operating-temperature degradation
  at moderate temperatures on Ubuntu 24.04

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