Would you believe 70-80 dB noise level from a MacPro Tower?

trond · Post by **trond** » Sun Mar 04, 2007 5:46 am

I was pleasantly surprised at how quiet my new macpro was - the first few days I had it, all I was doing was installing software, and it sat next to me in the home theatre while I fed it DVD's, or files to copy over the ethernet. The loudest noise was the DVD drive head, it was surprisingly quiet and I was mightily pleased with my brilliant purchase.

Then I moved it into the computer room (adjacent to the studio), and connected it up to the audio interfaces. Now the fan has kicked in - it seems to simply run at high speed all the time - and it seems very noisy. Noisier than my quicksilver G4 Dual Gig by far, noisier than my home built rack mount PC nearby from which I have removed the top cover for the time being.

I measured the sound level with a Sound Level Meter - keeping the sensor at least a few inches away from the outer body of the MacPro itself, I get readings of 75 dB in front, and about 70 dB in the rear (fan running at full speed). The sound is like that of a table saw running freely in the distance, there's even a specific note associated with the noise. Surely this can't be normal??

Trond

gregwhartley · Post by **gregwhartley** » Sun Mar 04, 2007 2:46 pm

Wow, that sounds pretty extreme for fan noise! How bad is it from mixing position (dB-wise)?

trond · Post by **trond** » Sun Mar 04, 2007 6:26 pm

I can't hear it from the mixing position, which is in the next room.

Anyway, it appears problem has gone away. I shut down, then rebooted and the macpro has been silent all day long.

I can only guess that somehow the fan controller had a fit, and got stuck in the 'max' position somehow ...

monkey man · Post by **monkey man** » Mon Mar 05, 2007 4:59 am

This used to happen with my old mirror-door turbo-blower G4 dual 867.
Same problem and cure; I believe it was not uncommon.

Could this be a clue as to the heritage of the controlling mechanism?

Phil O · Post by **Phil O** » Mon Mar 05, 2007 6:48 am

Wow. That seems excessive. Mine is VERY quiet. Is the room you moved it to much hotter? Does your RAM have the big Apple style heat sinks?

Something sounds wrong. (no pun intended)

Phil

auptown · Post by **auptown** » Mon Mar 05, 2007 10:28 am

One thing, I have had Mac's that got weird about fans and stuff, and then I did a reset PMU (Power Management Unit) and that corrected it. I don't know the procedure on that box, but you may want to give it a try.

trond · Post by **trond** » Wed Mar 07, 2007 6:43 pm

Others at the apple forum report having this problem. It apparently is associated with a problem on the logic board that controls fan speed. One guy got a replacement computer, the other is having his logic board swapped out. Apple has a wait and see attitude in my case, since it has happened only once so far ...

My RAM has all the right heat sinks, the room is large and cool, the power is clean and ample -

Trond