PowerMac G5 2.7 GHz: 86°-93°, when running longer even up to 102°
@geit: Thanx for explanation. Now I know why fans under MOS run always at full speed (quite noisy). The machine is really a lot(!) faster than my G4 1.5 GHz. Watching 1080p Videos at full speed and having just 35% CPU usage is really cool. But cause of the noise I doubt the G5 will replace my G4 as my main machine. It's a pity.
I was surprised that the temperature is already 86° immediately after switching on the machine, even if ist wasn't used for hours...