Running fans at 100 %

Discussion in 'MacBook Pro' started by wedda, Aug 23, 2014.

  1. wedda macrumors member

    Aug 11, 2014

    Is there anyone out there who have used their MBP with the fans set to 100 % for a longer period of time?

    I assume apple benchmarked them very hard and they would last even if they go at 100 % for a long period of time?

    Or will it actually harm them and cause them to be damaged pretty easily?
  2. GGJstudios macrumors Westmere


    May 16, 2008
    Why would you have fans running at 100% all the time? There's no need to. Your Mac can manage fan speeds according to the demands on your system, without any user interference.

    If you're not already doing so, use iStat Pro (free) or iStat Menus ($16) to get accurate readings of your temps, fan speeds, etc., rather than relying on your sense of touch or sound. A forum member has posted a copy of iStat Pro that has been "tweaked" to enhance compatibility with recent OS X versions. You can download it here.

    If your fans are spinning up without increased heat, try resetting the SMC.
  3. DeltaMac macrumors G3


    Jul 30, 2003
    The fans are ALWAYS running.
    You may reduce the fan's life by running at full speed.

    There may be alternatives to forcing the fans to high speed, such as a house fan, or a "cooling pad"

    What do you mean by "long period of time"

    10 minutes or so - OK
    10 hours or all day - until you sleep or shut off your Mac - probably excessive.
    Leave your Mac on 24/7 and set your fans at full speed permanently - not a good idea.

    You should also find out why your MacBook Pro runs so hot. The fans may just need cleaning, or the heatsinks can be clogged. Either are best cleaned by opening up your MBPro, and cleaning manually, usually just with air, or brushing carefully. If your MBPro is several years old, you can also consider redoing the heatsink thermal paste.
  4. wedda thread starter macrumors member

    Aug 11, 2014
    When I game in bootcamp I let them run at full speed so I can game more fluently. The GPU runs too hot otherwise and will clock down - I don't want that...

    I have a cooling pad as well, so it helps a little bit I assume...

  5. simon48 macrumors 65816


    Sep 1, 2010
    I think that would be just fine.
  6. Dilster3k macrumors 6502a


    Jul 20, 2014
    You'd have to imagine how not-so durable those fans are within the thin chassis. I would never leave them on for hours on, I'd let the OS do the heat management. Besides, you could even let more dust build inside your machine.
  7. wedda thread starter macrumors member

    Aug 11, 2014
    I run the fans at about 3500 constantly now, since my CPU runs at 70 degrees while being maxed.. When my GPU loads as well they run maybe at 4000-5500 so I dont' really need them going at full speed it seems. :)

    Attached Files:

  8. john500y2k macrumors member

    Feb 28, 2013
    I would imagine that anyone that plays games for long periods of time on their MacBook would be a good gauge.

    I play simcity on my MacBook for some very lengthy sessions often stretching to 8-12 hours without stopping throughout the day as I go about doing the house stuff.

    Obviously while the game is running it has a high CPU & GPU requirement so the fans are constantly on full. At first I was a little concerned about the wear & tear but I must have played for a total of something like 270 hours and not noticed any degradation in my fans yet. Plus all the other times the fans would have kicked into high while not gaming.

    I just went into the apple store yesterday regarding image retention and they traditionally ran the full hardware tests and the fans came back as completely functional. So again so far so good. So I'm glad I didn't constantly go the route of being paranoid about using the laptop for long times with fan on full.

    I know they are mechanical so they will eventually fail but I would never force on my fans to full just because I wanted to. Just let the laptop manage and use it as you want to without thinking constantly about failures. If they happen they happen but at least you got to use your laptop the way you wanted too.

    Dust build up is a completely different matter. Took the bottom off my rmbp a year after I got it and although it wasn't horrid like I've seen sometimes it was defiantly worth a clean.

    Hopefully they gave it a quick blast out while they changed my screen yesterday.
  9. maflynn Moderator


    Staff Member

    May 3, 2009
    I don't game, but I suspect if you run your fans at 100% all the time, you'll wear out the bearings in the fans. The fans were not designed to be run full blast all the time and I think that will out cause excessive wear and tear on that component.

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