2 Replies Latest reply: Feb 7, 2012 8:33 PM by den.thed
Big Josh Level 1 Level 1 (5 points)

When the room is very quiet, I hear an intermitent "purring" noise that seems to come from the top right corner of my new iMac. It sounds as though a fan is not balanced, or I suppose it could be a hard drive noise too, but I've never heard anything like it. The first two weeks that I owned this iMac, it was silent. Now I have an intermitent noise. It just sounds like something is coming loose. It doesn't seem to effect performance, but it bugs me.

 

Is it normal?

 

Is there anything I can try that might fix it?

 

Is there a test process that will wind the fan(s) way up, that might straighten things out?

 

Any suggestions appreciated.


iMac (21.5-inch Mid 2011), Mac OS X (10.7.3)
  • ESSamuel Level 1 Level 1 (0 points)

    If the sound come from the top right corner it is probably the DVD reader since there are only the CPU cooling and the DVD on the corner. The fan are at the bottom and center of the computer and the HDD at the top center. Sadly I cannot help you to solve your problem as I never had that sound.

  • den.thed Level 7 Level 7 (25,180 points)

    Big Josh wrote:

     

    When the room is very quiet, I hear an intermitent "purring" noise that seems to come from the top right corner of my new iMac. It sounds as though a fan is not balanced, or I suppose it could be a hard drive noise too, but I've never heard anything like it. The first two weeks that I owned this iMac, it was silent. Now I have an intermitent noise. It just sounds like something is coming loose. It doesn't seem to effect performance, but it bugs me.

     

     

    Start off by visiting > iMac: Evaluating normal noises

     

    Big Josh wrote:

     

    Is it normal?

     

    Depends, the CPU fan in my Early 2006 Core Duo purr's a little at it's default speed of 1000 RPM. However if I run it up a mere 200 RPM to 1200 RPM, then it runs nearly silent and has for the last 6 years.

     

     

    Big Josh wrote:

     

    Is there anything I can try that might fix it?

     

     

     

    1. Take the iMac into your local Apple Store or Apple Service Provider and see if you can get them to listen..?

    2. Test each of the three fans (HDD, CPU and Optical Drive) one at a time by slowly running each one up a few hundred RPM and then back to default.

     

     

    Big Josh wrote:

     

    Is there a test process that will wind the fan(s) way up, that might straighten things out?

     

     

    The only test that I can offer is smcFanControl, however you will want make sure that you fully understand how the utility works before using it.

     

     

    Big Josh wrote:

     

    Any suggestions appreciated.

     

    One other suggestion, is to get and use the iStat Pro, a Dashboard Widget by iSlayer as a secondary monitor for fan speeds, temps and other processes.