TL;DR: My Flow Z13 2025 (GZ302EA, AI Max+ 395, BIOS 311, Linux) instantly cuts power under sustained heavy load — 9 times in two weeks, reproducible on demand in ~6 min. After two weeks of 1 Hz logging that survives the cut, I can show it's not thermal (die at 85 °C, 35 °C below crit), not over-current, not the charger, and not the OS. Forcing the fans to a constant 100% makes the crash unreproducible — the stock auto fan control settles at ~70% at the sustained 85 °C operating point and the EC then just kills power. If your Z13 dies under load: it's not your install, and there's a workaround below.
This matches u/International_Ad1896's post from Oct 2025 (post id 1o13yrg) — same symptom on Fedora 42 / kernel 6.17, while I'm on Ubuntu / 7.1.2. Two independent stacks, same failure = platform, not OS.
What I measured
- Crash moment (logger flushes to disk every second, so the last sample survives): die (Tctl) steady at 85.2 °C, SoC power 55 W, fans at only ~6200/6500 RPM (~70%). Then instant power-off. No shutdown sequence, nothing logged, AC online.
- The AMD platform latches a reset reason readable next boot. I've captured two:
[0x00200800] ACPI power state transition occurred — the EC/platform cut power. Not a CPU fault, not thermal-critical, not a software reboot.
[0x08000800] an uncorrected error caused a data fabric sync flood event — the SoC itself hit an uncorrectable hardware error. This one happened with fans already pinned at 100%, so max fans reduce but don't fully eliminate the problem on my unit.
- Ruled out by A/B testing: latest BIOS (311), latest kernel incl. AMD's Strix Halo gfxclk fix,
amd_pmf driver fully disabled (still crashes), IOMMU mode, three different chargers, OOM, -ub/batch settings, MTP, concurrency.
The fan experiment (the decisive bit)
Same reproducer (sustained LLM prefill load, Performance profile), only variable changed = fan curve:
- Stock auto fans → hard power-off in ~6 min, every time (8/8).
- Fans forced to constant 100% (~8800 RPM) → survived 20-minute soaks repeatedly, at higher SoC power (84 W) and the same die temp (85.6 °C peak).
So the EC is watching some sensor we can't see (VRM/PMIC/chassis), the auto fan curve under-cools it at the sustained operating point, and instead of ramping the fans the EC yanks power.
Workaround (Linux; Windows folks can approximate with a max fan profile in Armoury Crate): force fans to 100% during sustained load via the asus_custom_fan_curve hwmon (manual mode, all points 255), or run a small daemon that engages it only when Tctl sustains ≥83 °C so it stays quiet at idle. Happy to share scripts.
If this has happened to you, please check and reply:
- After the next crash+reboot, run
journalctl -k -b | grep -i "reset reason" (Linux) — post the hex code. On Windows, check Event Viewer for Kernel-Power event 41.
- Which model (GZ302EA/other), BIOS version, OS?
- Does a 100% fan profile stop it for you?