Mac Pro fan pulses - is it normal?

Discussion in 'Mac Pro' started by Thunderbird8, Aug 25, 2009.

  1. Thunderbird8 macrumors regular

    Thunderbird8

    Joined:
    Dec 11, 2007
    Location:
    UK
    #1
    The fan in my Mac Pro (new March 2008, not the fan, the system) even though it is very quiet, sometimes makes a kind of pulsing noise. It is not what you would call noisy but it is getting on my nerves as my office is often very quiet, indeed silent.

    Is it normal?
     
  2. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #2
    ??? :confused: ???
     
  3. Thunderbird8 thread starter macrumors regular

    Thunderbird8

    Joined:
    Dec 11, 2007
    Location:
    UK
    #3
    Whilst your comment is indeed insightful I'm not sure it entirely reaches the heart of the matter.

    The. Fan. Pulses. Rather. Than. Being. Constant.
     
  4. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
    Location:
    Japan
    #4
    I still don't get it. I need a better description than that to know what you're talking about.

    Maybe someone else can mind-read?


    Anyway, whatever the description, the fans should not pulse in any way that would give rise to that adjective as a description. So, no. It's not normal.
     
  5. Thunderbird8 thread starter macrumors regular

    Thunderbird8

    Joined:
    Dec 11, 2007
    Location:
    UK
    #5
    The fan, rather than always seeming 'on', sometimes makes a kind of oscillating or pulsing noise. It's the sound of a fan pulsing or oscillating. I can't describe it any better than that I'm afraid.
     
  6. lannister80 macrumors 6502

    lannister80

    Joined:
    Apr 7, 2009
    Location:
    Chicagoland
    #6
    Like the RPM is going up and down, up and down. I understand what he's saying. No, it's not normal. :(
     
  7. bearcatrp macrumors 68000

    Joined:
    Sep 24, 2008
    Location:
    Boon Docks USA
    #7
    Install smcfancontrol and raise the fan rpm's to see if it goes away. Am thinking its a harmonic hum coming from your disk drives though but not real sure. If you raise the rpm's and find thats not it, place your hand on top of the pro and press down firmly and see if that does it. My old 2006 mac pro had something like that and found out it was the 4 drives doing this.

    Just to add, use istat widget to watch the fan rpm's to see if they are going up and down. When is the last time you blew the dust bunnies out of the pro?
     
  8. UltraNEO* macrumors 601

    UltraNEO*

    Joined:
    Jun 16, 2007
    Location:
    近畿日本
    #8
    You know, it would be a nice idea if some hardware manufacturer could come up with a desirable solution to in-take air filtering. It might help reduce the amount of dust in our systems. Three weeks ago, I did that house keeping for my two boxes and together both MP's managed to filled my dyson with fur balls! :eek::eek:
     
  9. sos85 macrumors member

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    nw2 7jp Londo
  10. gugucom macrumors 68020

    gugucom

    Joined:
    May 21, 2009
    Location:
    Munich, Germany
    #10
    I had fan noise from my Mac Pro by a curious mishap sometime. I fitted a better fan unit to my 3870 graphics card which ended up having slightly higher fixtures at the back of the card. Now the four nuts holding the fan connected with the metallic RAM cage. It gave me a sound that drove me nuts for a day. I inserted a piece of paper and the noise was gone.

    In another instance my main fan unit wasn't fitting correctly. I found out that one of the black labels of the Foxxconn cable set was caught between the logic board socket and the fan unit connector. After clearing the obstacle the fan unit mounted much easier and the noise was gone.
     
  11. Tesselator macrumors 601

    Tesselator

    Joined:
    Jan 9, 2008
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    Japan
    #11
    Why would he clean his notbook in order to solve intermittent fan noise in his Mac Pro?
    :confused:
     
  12. LurchNC macrumors regular

    Joined:
    May 1, 2008
    #12
    I had a similar "pulsing" noise coming from mine. It turns out its the case itself. If I lift the lever in the back that locks the door on it goes away. I just leave that lever up now. I think it's the hard drives vibrating slightly, causing the case to hit it resonance frequency.

    That may not be your problem, but give it a shot.
     
  13. benborman macrumors member

    Joined:
    May 28, 2008
    #13
    When I first bought my Mac Pro, I had 2 hard drives - one in each of the first two bays. When I added a third, I started noticing the pulsating vibration. I searched the forums and found different users posting various remedies, some a ghetto as shoving cut up strips of a towel into their Mac, some more refined, like using rubber washers between the drive and drive sled. I now have all four HDD bays occupied, mounted with rubber washers, and I only occasionally get "the hum" (it kind of worked itself out). A quick bump to the top of the computer (the handle) solves it most days.

    OP - Determine whether your problem is the fan or a vibration before messing with the fan speeds.
     
  14. UltraNEO* macrumors 601

    UltraNEO*

    Joined:
    Jun 16, 2007
    Location:
    近畿日本
    #14
    Huh? I think you've clicked on the wrong section... lol :confused:
     

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