Here's a way to fix (kind of) MBA left hand rest heating problem

Discussion in 'MacBook Air' started by Marconelly, Jul 5, 2008.

  1. Marconelly macrumors 6502


    Jul 5, 2008
    I'm sure all Air users are familiar with this, I've seen this complaint many times on message boards. MBA's left hand rest gets really warm after some time of continuous use. Uncomfortably so.

    I found that the way to "fix" this is to just switch the AirPort off. Left hand rest cools down within a minute of having Airport switched off. Now of course this is not much of a fix if you need wireless internet or file sharing, but it can come very handy if you don't need it, as the hand rest will heat up even if the wireless connection is completely inactive, as long as the Airport is enabled. I wish there was some app that would switch it off automatically after a period of inactivity, but for now, you have to switch it off manually (by going to the little wireless menu icon on the menu bar and selecting "Turn AirPort Off")

    I tried search for this tip on the forum but couldn't find it, hopefully I'm not just restating something that's already well known.

    Heating in general seems to be an issue with MBA. It's weird that even when my CPU temperature is around 50 all the time, and all other temperatures are below that, the fan just goes to 6200RPM after a while, and it takes it forever to go down (usually if I just stop doing anything other than reading text document for a while, for example) This happens with CoolBook installed, and all voltages set to just 0.9V btw. The machine still won't stop amping that fan, which even at 6200 doesn't really seem capable of cooling it down :\ I actually wish SMCfancontrol would allow me to limit the top speed of the fan - why should it ever go to 6200 when the CPU temperature never goes above 55, and when it seems 4000 RPM does as good (or bad) job cooling it down as 6200 does?
  2. brendanryder macrumors 6502a


    Dec 28, 2006
  3. Marconelly thread starter macrumors 6502


    Jul 5, 2008
    Yes, sorry about that. It seems like the board created two same topics because I wasn't logged in when I clicked Submit. I have asked mods to take care of it, and now they have.
  4. ayeying macrumors 601


    Dec 5, 2007
    Yay Area, CA
    My left palm rest does not have a heat problem... its cool regardless what load or ambient temp since theres nothing under it except the battery. However, the charging port does emit a lot of heat, which can interfere with the fan sensor, in-turn, causing the fan to spin at 6200 even when the CPU is cooled.
  5. jont-fu macrumors regular

    Mar 13, 2008
    Actually, it is possible to limit the max fan speed with smcfancontrol. Only limiting it to 5000 RPM lowers the noise significantly. You can find the instructions and a table of speeds in hex at this thread:

    I haven't noticed my left hand rest heating that much to cause discomfort, perhaps it's connected to the signal strenght of your base station? Weaker signal needs more gain on input and power on the output stage.

    What I have noticed is that the fan seems to react more to the enclosure base temperature than CPU temp. I seldom get fan noise when the MBA is on a table, but whenever I use it on my lap for a longer time (being careful not to block the vents) the fan revs up. It's way easier to sink heat into a room temperature table than into a 37C human body :)
  6. phinnaeus macrumors member

    May 19, 2008
    North Carolina, USA
    I agree with this. And thanks for the tip on maxing the fan control :D.
  7. sir. mac macrumors regular

    Nov 21, 2006

    I find that 4000RPM is plenty. Little or no difference from the original 6200RPM. I´ve tried 4000RPM while watching HD-movies and the difference from 6200 is just a few degreees celsius.
  8. Marconelly thread starter macrumors 6502


    Jul 5, 2008
    That's great news! Thanks a lot for that tip, I'll give it a shot. I do have a pretty weak wireless router now that I think about it. I should really test Air with some stronger one and see how it goes. If it stops the heating, it will be worth buying bigger router for that alone.

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