UX: CPU overheating on laptops during installation — suggest adding cpu limit guidance

[jaimealberto]

Description

On laptops and low-TDP hardware, the QEMU/KVM process sustains 100% CPU usage during Windows installation, causing dangerously high temperatures (89–94°C observed on an Intel Core i7-6600U with a 15W TDP).

The container has no default CPU limit, so on constrained hardware the installation phase can push the CPU close to its thermal throttle/shutdown threshold.

Observed behaviour

• Container CPU usage: ~244% during Windows 11 installation
• CPU temperature: peaked at 89°C (critical threshold: 100°C)
• Fan at maximum RPM throughout

Workaround (discovered during testing)

CPU limits can be applied live, without restarting the container, using docker update:

# Reduce CPU allocation on the fly if temperature spikes
docker update --cpus="1.5" windows   # moderate — reduces temp significantly
docker update --cpus="0.7" windows   # aggressive — for stubborn cases

# Restore after installation is complete
docker update --cpus="2.0" windows

This immediately throttles the container and brings temperatures down (89°C → 68°C in ~5 seconds in our test).

Suggestion

Consider one or both of the following:

1. Add a note in the README for laptop/low-TDP users recommending they set a CPU limit during installation:

   deploy:
     resources:
       limits:
         cpus: "1.5"

2. Mention docker update --cpus as a live throttling option if temperatures spike mid-installation.

Environment

• Hardware: Lenovo ThinkPad X270 (Intel Core i7-6600U, 2 cores / 4 threads, 15W TDP)
• Host OS: Debian 13 (trixie)
• Docker: 29.5.0
• Container image: dockurr/windows (latest)
• Windows version: 11

[LIxyLGy75LhmG]

Implementing a CPU limit in the container's deployment configuration as suggested could prevent overheating during installation; also, consider adding specific temperature thresholds for Intel CPUs in the README to guide users better.