Buzzing CPU when idle since Lion?

Discussion in 'Mac Pro' started by b.lam, Jul 22, 2011.

  1. b.lam macrumors member

    Sep 5, 2010

    I have a 2010 Mac Pro with a 3.2GHz quadcore. I noticed a buzzing noise if the CPU load is below a certain threshold. This did not occur with SL and also does not happen when running Windows in Bootcamp.

    The buzzing sound cannot be heard e.g. when scrolling through a complex webpage or transcoding something with handbrake.

    Has someone else experienced the same issue?

  2. spidey3 macrumors regular

    Jul 1, 2010
    Where is the buzzing noise coming from? Fans? Internal speaker? Drives?
    Does it happen when the case is open?
  3. b.lam, Jul 22, 2011
    Last edited: Jul 22, 2011

    b.lam thread starter macrumors member

    Sep 5, 2010
    It's coming somewhere from the lowest compartment where the CPU and RAM are located and can be heard as well if the case is open.

    It's definitely not coming from a fan or a disk.

    Update: I have removed the CPU board and put it back in. Now the buzzing sound can still be heard but is much quieter than before.
  4. b.lam thread starter macrumors member

    Sep 5, 2010
    Waking my Mac this morning, the buzzing noise is there again :mad:

    Isn't there a tool somewhere in Xcode with which the sleep modes of the CPU can be adjusted? I darkly remember something like this.
  5. Cindori macrumors 68040


    Jan 17, 2008
    I'm guessing you mean coil whine. CPU's doesnt coilwhine, but motherboards/psu/gpu do. It's most common on GPU's.
  6. b.lam thread starter macrumors member

    Sep 5, 2010
    Might be a coil or a capacitor, but it's loudest placing my ear next to the CPU board.

    But why does this happen only in Lion, not in SL or Windows? And how could I possibly fix it? Removing the CPU board and putting it back in (which solved it yesterday) is not the best approach :D
  7. b.lam thread starter macrumors member

    Sep 5, 2010
    OK.. I seem to be the only one having this problem. The apple discussion forums also did not help.

    I switched back to Snow Leopard for now. I keep my Lion partition and will take a look again when 7.1 is available. Until then Snow Leopard will be my first choice.

    Since I also experienced several freezes after rebooting, I rate this OSX update the worst since 10.0. Up to now, I was quite happy about Apple and OSX, but Lion is definitely still in beta (or even alpha?) phase. Every major OSX update has been more stable and reliable than Lion.

    It's good that I am also used to Linux and Window and W7 is quite good (despite the fact that it always tries to 'eat' your hardrive). I'm starting to consider a normal PC for my next purchase.
    Thanks Apple, it's been nice for the past 11 years, but with your latest decisions (e.g. only glossy screens for iMacs *headache*) and the improvements of other plattforms I tend to say goodbye :-(

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