[SOLVED] Radeon 780M: Thermal throttling to 800Mhz until entire laptop chassis cools off

Framework Laptop 13
1

Which Linux distro are you using?

Fedora

Which release version?

40

Which kernel are you using?

6.10.11-200.fc40.x86_64

Which BIOS version are you using?

3.05

Which Framework Laptop 13 model are you using?

Ryzen 7840U, (64 GB)

Problem

Under certain workloads (e.g. gaming), my clocks normally average at around 3.3 GHz (CPU) and 2.1 GHz (shader clock). Once the GPU temp hits 93ºC, it caps to 1.1 GHz (CPU) and 0.8 GHz (shader clock). This behavior persists until I:

  1. Let it cool off completely, the entire chassis. Just letting the CPU/GPU cool down to 40ºC is not enough
  2. Turn the laptop off completely for a few seconds and boot again

This issue normally occurs after 1 or 2 hours, but I can reliably reproduce it in ~20 minutes if I put my laptop onto something that impairs airflow (e.g. bedsheets). Gaming mode makes no difference, and neither does Fedoras performance power mode. No issues in dmesg.

Thought: Maybe its not the gpu, but a nearby component that also heats up? (E.g. ram or a chip on the motherboard).

2

I did more testing and clocks can reset without a reboot. But that only happens after the entire laptop cools off completely, long after the CPU/GPU have reached 40ºC.

I found that AMD CPUs have a safety feature called STAPM (Skin Temperature-Aware Power Management), which applies throttling based on the laptops chassis temperature. The limit defaults to 42ºC, so I’ve installed ryzenadj to increase the value via --apu-skin-temp 60. This has helped people with similar problems [1][2][3], but made no difference on my machine. So I left the default 42ºC and saw it getting surpassed long before the throttling happens. It is probably a different component in the laptop that causes this(?). RyzenAdj has some other flags that I’ve tried, but I was not able to force a clock speed reset.

People had some success with UXTU, [4], the windows-counterpart to RyzenAdj. I probably have to investigate which values they set there. Maybe its posible to replicate UXTUs “extreme” mode with RyzenAdj.

Another thread with people describing issues similar to mine, but those solutions did not work for me either: Gaming Throttling - #28 by BigT

3

Interesting, I didn’t know that did anything below 80C.

4

Throttling depends on my rooms temperature, with a few degrees making all the difference. At 20.5ºC or below, it practically never happens. Up to 21.5ºC I occasionally notice a slight drop in gameplay smoothness/framerate. And above 22.5ºC it always throttles to 800 MHz after 20 to 35 minutes of heavy use.

I did more investigation into ryzenadj and found these presets [1] ported from the windows tool UXTU [2]:

PRESETS = {
    "Eco": "--tctl-temp=95 --apu-skin-temp=45 --stapm-limit=8000 --fast-limit=10000 --slow-limit=8000 --vrm-current=180000 --vrmmax-current=180000 --vrmsoc-current=180000 --vrmsocmax-current=180000 --vrmgfx-current=180000",
    "BalPreset": "--tctl-temp=95 --apu-skin-temp=50 --stapm-limit=15000 --fast-limit=18000 --slow-limit=15000 --vrm-current=180000 --vrmmax-current=180000 --vrmsoc-current=180000 --vrmsocmax-current=180000 --vrmgfx-current=180000",
    "PerformancePreset": "--tctl-temp=100 --apu-skin-temp=50 --stapm-limit=28000 --fast-limit=35000 --slow-limit=28000 --vrm-current=180000 --vrmmax-current=180000 --vrmsoc-current=180000 --vrmsocmax-current=180000 --vrmgfx-current=180000",
    "ExtremePreset": "--tctl-temp=100 --apu-skin-temp=50 --stapm-limit=35000 --fast-limit=60000 --slow-limit=35000 --vrm-current=180000 --vrmmax-current=180000 --vrmsoc-current=180000 --vrmsocmax-current=180000 --vrmgfx-current=180000",
    "AC": "--max-performance",
    "DC": "--power-saving"
}

The “performance” and “extreme” presets fix my problem. Both perform the same in terms of gameplay and framerate, but the extreme preset runs much hotter (100ºC CPU). This causes some occasional framerate fluctuation, so I just stick with the more consistent “performance” preset.

5

Solution (Linux)

  1. Disable secure boot (this can be avoided with quite some work, but DIY for that)
  2. Add iomem=relaxed as a cmdline argument to your kernel (/etc/defaults/grub and sudo grub2-mkconfig -o /boot/grub2/grub.cfg)
  3. Reboot
  4. Download and build RyzenAdj as described here
  5. When your system starts throttling, run sudo ./ryzenadj --tctl-temp=100 --apu-skin-temp=50 --stapm-limit=28000 --fast-limit=35000 --slow-limit=28000 --vrm-current=180000 --vrmmax-current=180000 --vrmsoc-current=180000 --vrmsocmax-current=180000 --vrmgfx-current=180000

Notes

  • Stopping your workload and letting your laptop cool off will reset the power profile. Afterwards throttling can reoccur, in which case you have to reapply the command above. But as long as your workload keeps running, the performance profile you’ve set via ryzenadj will stay
  • While this solution fixes throttling to 800 MHz, there will still be some performance/framerate loss if the laptop gets too warm. So refer to common knowledge like proper airflow, dust in heatsink, room temperature, lid open vs closed etc.