Slow fan at 217+ degrees?

Discussion in 'MacBook Air' started by wonderboyP8NT, Mar 11, 2013.

  1. wonderboyP8NT macrumors newbie

    Jul 8, 2012
    Im hoping someone can help me diagnose an issue or recommend a course of action. When the macbook air starts playing a game or encoding video it gets really hot, but the fans do not kick in. Eventually the performance drops as the processor starts throttling and the fans are still at their slowest speed. I installed iStat menus to track the temps and fan speed. I have seen the temp as high as 220 with 2500 rpm fan speed...

    So far I have tried re-installing OSX and re-installing iStat menus. The fan appears clean as well. I am wondering if I may have done something. I do a lot of stuff in terminal such as disabling saving ram to disk on sleep, etc.

    Any thoughts? Any help is greatly appreciated.

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  2. GGJstudios macrumors Westmere


    May 16, 2008
    Try resetting the SMC.

    The Intel processors used in Macs are designed to automatically shut down to prevent damage if they truly overheat. CPU Tjmax = 105C (221F), GPU Tjmax = 100C (212F) on i3, i5, i7 processors. (Source: Intel)

    Unless there is a rare defect in a Mac, most temps are well within the normal operating range, considering the workload being put on it. Websites with Flash content, games and other multimedia apps will put higher demand on the CPU/GPU, generating more heat. This is normal. If high demands are consistently put on the system, such as gaming or other multimedia tasks, expect temps to rise and fans to spin up accordingly. It's just the Mac doing its job to maintain temps within the normal range.

    It is also quite normal for a Mac to become extremely hot to the touch during intensive operations. The aluminum body transfers heat more effectively than other materials used in computer casings, so the heat is more easily felt on surfaces. This doesn't indicate that it's overheating and will not harm the computer to be hot to the touch.

    The fans are always on when a Mac is on, spinning at a minimum of 2000 rpm (for MBPs) or 1800 rpm (for MBAs, MBs and minis). iMacs have 3 fans with minimum speeds in the 800-1200 range. They will spin faster as needed to keep temps at a safe level.

    If the fans are spinning up without increased heat, try resetting the SMC.
    (PRAM/NVRAM has nothing to do with these issues, so resetting it will not help.)

    The intake and exhaust vents are in the back of the computer near the hinge on all Mac notebooks (except the new MBP with retina display, which has intake vents along the sides at the bottom). The iMac vent is a slot on the back near the top of the computer. Make sure the vents remain unblocked to allow the computer to perform at its best.

    Learn about the fans in your Mac
    Apple Portables: Operating temperature

    For Flash-related issues:
  3. wonderboyP8NT thread starter macrumors newbie

    Jul 8, 2012
    Thank you CGJ. So what you are saying is that even though the temp is at 217° which is about 98% of the processors TDP the fans will normally idle at 25% max rpm as the processor throttles itself? My MacBook Pro never did such a thing. I reset the SMC with no avail.

    Is it normal to have the processor throttle before max fan speed? That seems bizarre...
  4. GGJstudios macrumors Westmere


    May 16, 2008
    Usually the fans will spin up if high enough temps are sustained for a period of time, not just a brief spike in temps. If you're sustaining 100C+ temps for a period of time with no increase in fan speeds, you may want to have Apple check out your Mac to make sure everything is working properly.

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