I am still experiencing this same issue on a G5 single (not iMac) PowerMac 9.1. I am using Ubuntu 6.10 'Edgy Eft' beta PPC64 with all of the latest upgrades as per today. I wish we would get a solution soon as this has been going on since Ubuntu 5.10 'Breezy Badger'. -- iMac G5 Thermal Fan Support https://launchpad.net/bugs/34723