Fan Control - Why always +100 RPM from setting?

Discussion in 'MacBook' started by MBHockey, May 22, 2009.

  1. MBHockey macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #1
    I'm wondering if anyone else is having the problem depicted below.

    It's very consistent. The actual Base Speed that results is always 100 RPM higher than the Base Speed I set in Fan Control. Now, this isn't hard to workaround, but I'm wondering if anyone else is seeing such behavior.

    I like to keep the MB at around 1200 RPM when I am on battery power in the cafe. It saves a lot of power, and there is a negligible increase in temperature (on the order of 3-5 degrees F), and Fan Control has been great for that.
     

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  2. MarkMS macrumors 6502a

    Joined:
    Aug 30, 2006
    #2
    I don't know why, but I'm thinking it's due to the sensors and the coding from fan controlling apps. SMC Fan Control does the same on my older MBP. I set the fans to 2200 (up from default 1000), since the defaults on new MBPs are 2000 and it fluctuates from 2250-2300.
     
  3. MBHockey thread starter macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #3
    Really? smcFanControl works perfectly for me in that regard. The only downside is I can't set the fans lower than 1800.
     
  4. ppc750fx macrumors 65816

    Joined:
    Aug 20, 2008
    #4
    The SMC's control of the fans is relatively precise, but not *that* precise. :D
     
  5. pellets007 macrumors 6502a

    pellets007

    Joined:
    Jan 28, 2009
    Location:
    New York
    #5
    You do know that there is a reason, right? I don't think the benefits outweigh the risks in this case.
     
  6. MBHockey thread starter macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #6
    Do you understand what Base Speed is? It will only go that low if the conditions permit it. It's not setting the maximum fan speed. There's a not so subtle difference there I'm not sure you are understanding.
     
  7. pellets007 macrumors 6502a

    pellets007

    Joined:
    Jan 28, 2009
    Location:
    New York
    #7
    Aye, that I do understand; the manufacturers set their cooling devices into optimal level. But I'll leave your thread, as I cannot explain this anomaly nor do I have anything else to contribute.
     
  8. MBHockey thread starter macrumors 68040

    MBHockey

    Joined:
    Oct 4, 2003
    Location:
    New York
    #8
    I didn't mean to come off that harsh.

    I am just saying that I don't understand the argument that lowering the base speed is bad for the computer. I see it written a lot on here, and I think it bothers me because it's one of those things that nobody has cared to actually think about for a moment before perpetuating it left and right.

    Regardless of what speed the fans are running at, the OS will kick them to a certain higher value once a temperature threshold is surpassed, and then they will go back down.

    I have noticed that running the fans at 1100 RPM compared to 2000 RPM, with only Safari open, leads to ~3 degree F increase in temperature for the CPU. That is negligible. What isn't negligible is the battery power I get back from running the fans at nearly half speed. I get much more use out of the battery since it isn't uselessly spinning the fans. Not to mention, the machine is dead silent (there's an SSD inside too which helps reduce noise.)
     

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  9. pellets007 macrumors 6502a

    pellets007

    Joined:
    Jan 28, 2009
    Location:
    New York
    #9
    I didn't take it as such. ;)
     

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