Sleep issues with fans going on
I'm not sure if this helps but since the 10.5.1 update, my G5 won't sleep properly anymore. Fans just kick into full and it sounds like a jet engine. Can't wake it up and have to hold down the power button to shut it off. I think they call that a kernel panic... It would take me more effort to downgrade to 10.5.0 than to wait for 10.5.2
For the record, during normal work, fans seem normal, but they were normal before...