I have a g5 late 2005 dual core 2.3Ghz power pc. Leopard 10.5.8 I recently bought this, and could really do with some help understanding this problem, please.. All the fans come on the moment I press the on switch. I've tried many things - listed below, I've read zillions of threads on g5 fan issues, and now I've purchased 'hardware monitor' software, and found all sensor temps cool; and all fans are running. All are running at/near enough at the 'minimum specified rpm' which is handily also listed for each fan in this software. (but the noise level is about 3 times louder than my g4 - which I'm upgrading because it's so noisy!). I have briefly tried two of the earlier G5's, a dual 2.3, and a dual 2.5 (neither dual core), and they are both relatively completely quiet - no fans from switch-on at all, obviously they start to come on once there's a load on, but otherwise, no fan noise when idle. Question1: Is this (on all the time, at min speed) how they are supposed to run on this model of g5? surely not, 3 times louder than a g4? Question2: Can I reset the min speed, or some other edit to stop them being on all the time, through root- level editing? Question3: If so, what are the operating temperatures/minimum speeds they should be re-set to, in order to function well and safely? I've seen from forums that it's possible to adjust the inner settings of the 'thermostats' or temperature levels, that trigger, and ramp up, the fans, and also the minimum fan speed, but everyone on those forums wants to use this fix to increase fan activity. I want mine to stay still, or slow, until they are needed! Any help with this would be massively appreciated, as I bought this computer 10 days ago and must decide soon whether it's fudged and has to go back! Many thanks for reading this far! kk Things done so far: Since buying it I've wiped and re-installed, and updated OSX leopard - which fixed another issue of fans staying on, and speeding up, during sleep. Tried it with all connections removed, all pci-e cards removed including the graphics card, all extra memory removed, even with a blank HD - no OS installed. tried booting from DVD. I've cleaned it, checked the seals, reset everything, checked for firmware..