HT201834: Use your Mac notebook computer in closed-display mode with an external display

Learn about Use your Mac notebook computer in closed-display mode with an external display
Evelyn1015

Q: Hot Laptop

I am using an external monitor and keeping my macbook pro closed but I notice that the keyboard area of the laptop gets very hot.  Is this bad for the laptop?  How can i keep the laptop cool?

MacBook Pro with Retina display, Mac OS X (10.7.5)

Posted on Jun 13, 2016 7:16 AM

Close

Q: Hot Laptop

  • All replies
  • Helpful answers

  • by Limnos,

    Limnos Limnos Jun 13, 2016 7:47 AM in response to Evelyn1015
    Level 9 (53,622 points)
    Mac OS X
    Jun 13, 2016 7:47 AM in response to Evelyn1015

    This is a complicated subject which I have been dealing with the past day or two.

     

    There are sensors which report temperatures and there may be 10 of them. I think CPU Core temperature is one of the most useful but also a bit tricky to access.  I am currently using MacsFanControl (see it in the menu bar) which lets you see the proximity temperature which tends to underestimate core temperature by about 5°C, or diode temperature which over-estimates core temperature by about 5°C.  Hardware Monitor does a thorough report but when I ran it I was experiencing strange behavior in other things on my computer so I decided to go with a simpler tool.

     

     

    Temperature will also vary depending upon computer activity and room temperature.  Right now while just typing ASC replies my MacBook has a diode temperature of 57°C. Yesterday when processing video it was at 89°C.

     

    Apple specifications include operating temperatures but those are ambient (room) temperatures.  From what I have read online having a core temperature in the low-use range I see is perfectly normal.  89°C is high but when I do video the CPU is working 100% so may be expected. I'll just have to make sure if I do it not to do it on a day when it is 90°F in my room.  If things really get too hot a computer will (should) automatically shut down.

     

    MacsFanCotrol also reports fan speed.  Right now mine is working just above minimum which I interpret it thinking 57°C doesn't need reducing much.  When I was doing video it was running at maximum 6000 rpm.

     

    These are some of the things I tried to let my late 2008 MacBook run a bit cooler:

     

    - I got 4 rubber stoppers ("corks") and put them under the corners so there is more clearance under the computer and the case can be cooled.  This obviously only works when you have the computer sitting undisturbed.  I also try to have my room fan blowing in this direction so there's air moving under it.

     

    - I removed the back case completely (requires a tiny screwdriver) and used canned air to blow dust off the fan blades and clear the exhaust vents.  Be careful you don't freeze parts with canned air.

     

    - I have my computer also sitting on a cooling rack which is basically a couple of fans in a plastic tray which blow air onto the base of the computer. The model I have is almost useless but I got it for $1 at a garage sale to test.  You can get better models for $20+ (check reviews on Amazon).

     

    Obviously don't sit your computer on a fuzzy surface, or let anything block the exhaust vent at the back.

     

    All that said, I haven't actually felt the keyboard since I only use my computer in clamshell mode.

  • by BobHarris,Apple recommended

    BobHarris BobHarris Jun 13, 2016 8:16 AM in response to Evelyn1015
    Level 6 (19,272 points)
    Mac OS X
    Jun 13, 2016 8:16 AM in response to Evelyn1015

    The fan vents come out the laptop hinge.  When it is open it comes out the top between the keyboard and the hinge.  When it is close it comes out the bottom edge of the hinge in the back.  Make sure this is clear of any obstructions.

     

    Put your laptop on a riser of some kind to allow air flow under it.  A slight tilt wouldn't hurt to hot air flows up.

     

    And you can always just left it open if that is not sufficient.

     

    Also check to make sure you are not running CPU or Disk wasting apps in the background that are unnecessarily drawing more power that result in more heat.