Comment 11 for bug 23445

Francois (f-taiani) wrote :

(In reply to comment #10)
> Same problem on my iMac G5 1.8GHz. Disable the sound daemon seems to be a
> workaround. But after login, the fan starts up full speed.

This is due to newer monoprocessor G5 models using a new chipset for their cooling/power infrastructure. After a few seconds the firmware detects
there is no driver for the fans and kicks them into full speed for safety. The new infrastructure is called SMU and replaces the old PMU. Ben
Herrenschmidt (the main kernel developper for the ppc port) has been working on this. Experimental support for the SMU chipset should now be
available in the most recent kernels (>= 2.6.15, to be double-checked): see and

for more details.