Previous 1 2 Next 16 Replies Latest reply: Jan 11, 2008 8:53 AM by Seb Hughes
trainheist Level 1 (0 points)
hey; what's a good fan speed for smc fan control to set for a mac that'll spend most of it's day on; sleeping most of the day and every so often used for a few hours?


imac, Mac OS X (10.5)
  • DVD on iPod Video Level 2 (185 points)
    Hello trainheist,

    There is no real need for SMC FanControl as Mac OS X automatically keeps a track on the temperatures in you Mac and will automatically adjust fan speeds if you need to. Also, speeding up the fans for no reason will wear them down quicker.

  • trainheist Level 1 (0 points)
    actually no; my imac tends to shut off because it overheats after about 5/6 hours and i'm really not enjoying that. my smc fan control is preventing that now.

    Message was edited by: trainheist
  • DVD on iPod Video Level 2 (185 points)
    You should have made that clear!

    Anyway - I sometimes (when video editing) I only put the CPU fan to around 1500rpm.

    ODD and HDD don't have to be changed - there not as important.
  • trainheist Level 1 (0 points)
    i apologize. and as for the HDD and ODD fan speeds: what's the normal speed on something like that? smc fan control just sets it to minimum automatically.
  • DVD on iPod Video Level 2 (185 points)
    Well, on my 20" iMac the HDD fan speed is normally at 1400rpm and the ODD is at 800rpm. There is no need to change these. You can increase HDD to around 1800rpm just incase.
  • trainheist Level 1 (0 points)
    awesome, thanks for the help.
  • The Looby Level 4 (1,285 points)
    trainheist wrote:
    ... what's a good fan speed for smc fan control to set for a mac ...

    I think it depends on which iMac model you have. My 20" white 2.16 GHz
    has the following default fan speeds -- but I believe I've seen different
    defaults for ALU iMacs. They might also be different for 20" versus 24".

    ODD: default 800, maximum 5000
    HDD: default 1400, maximum 5000
    CPU: default 800, maximum 3600

    Also, on my machine, the standard fan control algorithm increases the
    speed of all three fans when the CPU temperature rises -- even if the
    HDD and ODD temperatures remain the same. I have no information on
    how the control algorithms would respond to high ODD or HDD temps,
    but I wouldn't be surprised if all three fan speeds increased.

    Here's a handy freeware app that allows you to raise the CPU temp by
    adding load to the CPU. If the fans don't respond, something's wrong.

    BTW, my iMac runs cool -- ODD, HDD, CPU all in the 35C to 38C range
    with all fans idling near their default speeds -- so, I've had no need for

  • trainheist Level 1 (0 points)
    um...i have no idea how to use this thing...
  • George Peters Level 4 (3,165 points)
    The default/maximum settings for an ALU iMac are:

    ODD: 700/4400
    HDD: 1200/5500
    CPU: 1200/3300

    When monitoring my iMac I found that it never once increased the fan speeds on it's own to adjust for an increase in temperature. So this is what I have my fans set to.

    ODD: 1055
    HDD: 1899
    CPU: 1734
  • Euripides Level 1 (25 points)
    I keep my white 2.16Ghz 20" iMac at the following settings during normal use:

    ODD: 1600
    HDD: 2400
    CPU: 1300

    I pretty much got to these settings by turning the fan up the most I could before them becoming noticeable. That way it is still quiet but not idling. If I run BOINC (maxes out processors) I have another profile to kick it up to 1750/2130/2530. This is still quiet while offering much more airflow/cooling. After building a PC and overclocking, I believe in running the fans as high as you will tolerate the noise to keep the components as cool as possible to prolong longevity and maintain stability. There is a noise-to-cooling tradeoff with fans, so it is really how much noise can you tolerate vs. how much heat are you comfortable with. Hotter is not better when it comes to component life/reliability.
  • onlyTan Level 1 (0 points)
    where can i get the fan control for the alu iMac from?

  • The Looby Level 4 (1,285 points)
    onlyTan wrote:
    where can i get the fan control for the alu iMac from?

  • George Peters Level 4 (3,165 points)
    Just in case it hasn't been mentioned in this thread I think most of us that have SMCFanControl are also using some other application to monitor the internal temperatures as well. This helps us to determine how to set the fan speeds. This way you can see the temperature results. I use Temperature Monitor but I know a few other people use the iStat Pro widget.

  • Seb Hughes Level 1 (25 points)
    Sorry to somewhat invade on this thread. I felt like it wasn't worth starting
    a new thread. Should the fans brake due to using SMC Fan Control to increase the RPM would this still be covered under apple warrenty or does it void it? Also what is the recommend max speed to set the fans to. Obvious 5000 would be stupid.
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