Throttle before fans?

Discussion in 'MacBook Pro' started by Lihp8270, Feb 12, 2017.

  1. Lihp8270 macrumors regular

    Dec 31, 2016
    i was having a look at istat menus and the intel tool.

    I noticed that at roughly 60c the cpu would throttle back slightly till the temps dropped back below 60c.

    But still the fans did not come on. This is a 2016 13" MacBook Pro with touchbar. 2.9ghz with 8gb ram.

    I've never really looked into the thermal management of my Apple stuff.

    But is it standard for Apple to cut the cpu speed before bringing the fans on?
  2. rutrack macrumors regular

    Jan 5, 2017
    No it's not, it should have started to blow heavy, unless the fans are restricted somehow.
  3. Sanpete macrumors 68020

    Nov 17, 2016
    Can you be more exact about the throttling? Did it just reduce the turbo boost? Also, what OS are you running?
  4. Lihp8270 thread starter macrumors regular

    Dec 31, 2016
    So this is a 2016 MacBook Pro, running the latest Sierra. I haven't noticed any performance issues, and this is purely my curiosity.

    It is 2.9GHz i5 which I believe has boost to 3.1GHz.

    Ambient temp is around 13-14c. CPU idles around 26c.

    Doing yes > /dev/null in terminal the CPU goes to 3.1GHz. As the temp goes over 50c, it drops the boost to 2.9GHz, but seems to then plateau at 50 to 52c.

    So I guess not really throttling but dropping the turbo boost. It is able to maintain it at 55c after 10 minutes, by dropping the boost. But still without any fans. I assume this is normal behaviour?

    As I have said, this is for curiosity.
  5. Sanpete macrumors 68020

    Nov 17, 2016
    I don't know if it's normal. It's just since the most recent Sierra update that you and @kbk75 have pointed out some peculiar curbs on turbo boosts. It may be that Apple has cut back some to save battery power. Both the turbo and the fan use up a little power. Would be interesting to know more about this.
  6. Lihp8270, Feb 12, 2017
    Last edited: Feb 12, 2017

    Lihp8270 thread starter macrumors regular

    Dec 31, 2016
    It only came about, as I was playing with iStat menus, noticed no fans running. I had originally assumed they were turning at low speeds, and Apple had done a good job on making them quiet.

    However, it peaked my interest to see how Apple was managing the thermals on this device. But through stress testing I cannot get the fans to come on, but I am in a cold room 13c (55F), so that may be helping the system somewhat. I don't want to push the temps too hard either, as the RH in this room is 68% so don't want to promote condensation :) (82% outside atm). I played with the fan settings on iStat Menu. But then decided to stop messing, turn them off and uninstall it.

    I did the SMC reset after just to be sure, and the fans do spin up with the Apple Hardware Test (which is quite neat, and the first time I had seen it). Maybe Apples thermal management is better than people give them credit for.

    I have not noticed any performance issues with this machine at all.

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5 February 12, 2017