I just got my replacement MacPro today(the first one had something wrong with its firewire ports), and I notice a jump in the Powersupply fans up about 250 rpm, from 600 to 850; and a jump in temperatures of about 20 celcius for both monitors in Istatpro for the powersupply temps. My first Macpro's power supply/power supply fan was 20 degrees cooler and ran at 250 less rpm. Also I noticed something strange when I first plugged this new mac in. When I connected a live power cord into the Mac, I heard 2 strange clicks coming from the powersupply. It repeated these 2 clicks when I disconnected it and tried it again. Its like everytime the powersupply gets a live feed introduced to it after its been unconnected, the clicks are present. Do you think the power supply is defective? The powersupply fans a whol? I read a thread here where someone returned it for these readings and got a replacement but I really dont want to do that for a second time. So the 2 clicks, the increased rpm, and increased temps now have me very frustrated as I just got this mac replaced because of faulty firewire ports. The only thing different however, is the powersupply activity. Temps such as the cpu areas actually seem cooler. I would like to get some feedback from other users with the "clicking power supply" when introduced to a live power cord. Perhaps its something like they forgot to remove a piece of plastic covering in the power supply fan area when it was built? That would explain the heat and fan, but not the clicking. Ok, but can anyone confirm that under idle conditions there Power Supply TEMPS are 70/63 for PS1/PS2. And higher temps as high as 80/70. My fan is running high, and my temps are running high. Can anyone confirm these numbers and tell me there normal for ( it seems atleast) the most recent macpro builds. Is there any program that will actually let you control the power supply fan? From the first mac I had its fan for the PS was around 600rpm, this one base lines at 790rpm. The temps are around 20 C higher on average. Thanks for reading.