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kernel_task CPU usage spikes when MBP is plugged in

1102 Views 5 Replies Latest reply: Dec 17, 2013 7:31 PM by DJWebDUck RSS
plemarqu Calculating status...
Currently Being Moderated
Dec 23, 2011 7:45 AM



Recently kernel_task has begun to spike to 500-550% whenever I have my MBP plugged in. If I unplug it kernel_task goes back to doing its thing at ~2% CPU and everything works fine (until of course I run out of battery). I'm running Lion 10.7.2. It has only started happnening recently (not right when I upgraded to Lion), and I cant think of any software or hardware changes I've made recently. Systematically shutting down processes has had no effect. Is there anything I can do to stop this from happening?


Any help with this would be greatly appreciated!





MacBook Pro, Mac OS X (10.7.2)
  • walkcoolboy Calculating status...
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    Jan 15, 2012 3:46 AM (in response to plemarqu)

    I have the problem reversed. When plugged in, everything is fine. If I unplug, it is extreme slow and kernel_task spike to ~200%

  • teedoo Calculating status...

    I had the exactly same problem.Have you fixed it? how?

  • walkcoolboy Level 1 Level 1 (0 points)
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    Oct 9, 2012 9:16 AM (in response to teedoo)

    Yes. I wen to Apple Repair Center. They changed mainboard for free. Since then my MBA is perfect.

  • J Herrera Level 1 Level 1 (0 points)
    Currently Being Moderated
    Apr 2, 2013 12:45 PM (in response to plemarqu)



    I am in kind of the same situation and it is driving me crazy!  Lately, the kernel task of my MB pro early 2011 goes over 300% and so it gets almost useless as it runs extremely slow. I took it several times to Madrid apple store,and hardware tests, again more hardaware test, format,cleaning its inside, and total reinstallation of the OSX were performed  several times without success: they find nothing wrong but later at home it happens again and again.  No more apps installed, new OSX... it can only be hardware, right?


    It led to awkward questions and situations as it didnt ever happen when in the apple store, but only at home. Anyway, genius bar people incredibly nice.


    I kept insisting, going back and finnally after reading these conversations here and explaining about it at the genius bar, they accepted to change the logic board for me. But sadly, it is happening again, and now i just dont know what else to do. If i take it back to the apple store, i dont know what else to say or explain, so far no problem has been found but it keeps happening.  It is so frustrating!!! It is such a shame to have to stop using my Mac normally  it is all more than perfect, but once the fan starts sounding loud, i know its back and no more use for a while.


    Can anyone help me or give me any advice?? I would really really appreciate it.


    Thanks in advance (and sorry for my english)

  • DJWebDUck Calculating status...
    Currently Being Moderated
    Dec 17, 2013 7:31 PM (in response to plemarqu)

    I was having the same problem but after days of googling I finally found a working solution:


         Mavericks System CPU Spikes When Unplugged


    It worked for me. Hopefully it'll work for you.


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