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MBA 13 (new model 2011) heats up rapidly after wake up from sleep

Hi! I bought the MBA in August and I have installed all the firmware and software updates. After installing the EFI 2.1. in September I have the following issue. When opening the lid of the MBA after several hours of sleep, the CPU temp rises very fast without doing anything on the MBA (no Internet, no wordprocessinh, no nothing). I have Temperature monitor installed and after 4-5 minures CPU gets 70-80 Celsius with fan working very loud. When I close the lid for 3-4 second and then open it again the CPU temperatures gets normal - between 40-45 degrees. With Internet it is around 50 degrees - no fan, absolutely calm.


I have made two Lion installs yesterday - one a clean install (erasing HDD), and one with preserving programs and data. No result, same behavior. I suspect that it has something to do with the deep state sleep in hybernate status. And I suspect it is problem with EFI 2.1., because prior to this the MBA reacted normally after wake up frim sleep. I goodled around, checked English and German forum, but not a hint or solution.


I can get accustomed to this second opening of the lid, but I don't think it's normal. By the way, when I shut down the MBA and start up after a night or so, there is no such behavior. Only after wake up after many hours of sleep.


Any ideas or solutions?


Leon 15

MacBook Air, Mac OS X (10.7.1)

Posted on Sep 19, 2011 11:39 PM

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34 replies

Sep 20, 2011 3:40 AM in response to Leon 15

Do you have a Time Capsule? I get the same heating/high activity behaviour and I have found that upon resuming out of sleep the Macbook is doing a backup to the Time Capsule. It seems that the accompanying Spotlight indexing of the backup means that the computer is doing quite a bit of work.


You can see what is going on by starting a Terminal and then using the top command to watch the active processes OR use the Activity Monitor application in the Utilities folder. I see lots of mdworker processes doing the work.


Now you can either ignore it as mostly harmless or you can change the Time Machine settings so that the Time Capsule backups are not indexed.


See here for more info: https://discussions.apple.com/thread/3218309


Hope this helps.

Sep 20, 2011 12:43 PM in response to markfromwillaston

Thank you very much for the suggestion!


Unfortunately I don't have a Time Capsule and the Time Machine is set to "off" from the moment I purchased the MBA. By the way I have checked the activity monitor twice during the heating up and there was no activity above 2-3 % of the CPU (I can't remember which process was exactly shown). I still suspect the EFI 2.1 as the culprit - I deeply regret that I have updated to it, because it's not possible to remove it anymore.

Sep 20, 2011 10:40 PM in response to Leon 15

I have a new MBA13 i5 purchased in August, and I am experiencing a problem similar to that expressed by the original poster. I use my air at work with no overheating issues (typical processor temp is around 50-55 C). At the end of the day, I close the lid, put it in my bag and go home, where I then continue to use the air at home. As soon as I wake the air at home, the temp increases to and stays around 80 C and the fan stays at 4K+. This high temp will continue, even though there is no significant CPU activity (max 1-2 %). I have ruled out the possibility of a rogue application or process by killing essentially every program that runs and/or monitoring the activity monitor.


If I do nothing else, the computer will stay in this high temperature state. However, if I force the computer to sleep then wake it up again, it goes back to normal behavior (temps around 50 C and the fan at 2K).


I have been able to repeat this behavior for several days now, although I only recently started experiencing this problem (maybe past week or so).


My best guess is a glitch in the OS caused by a software update.

Sep 20, 2011 11:36 PM in response to StevenRT

Do you have this problem from the very beginning, when you purchased your MBA? In my case it came after installing EFI 2.1. At the beginning I thought it was some kind of indexing and I let the MBA working at this high temperature (around 80 C) for maybe 10 minutes, but the heat and fan speed didn't slow down.


At the same time I'm asking myself what can cause the CPU to rise its temperature, when there's no major CPU activity!? Maybe it is a problem with the BIOS (I don't know how apple calls this, since I am almost two decades old Windows user), who knows.



Anyway, I can only confirm the information of StevenRT and I hope the Apple would fix this issue.

Sep 21, 2011 1:39 AM in response to Leon 15

At the same time I'm asking myself what can cause the CPU to rise its temperature, when there's no major CPU activity!? Maybe it is a problem with the BIOS (I don't know how apple calls this, since I am almost two decades old Windows user), who knows.

Modern Apple machines do not have a BIOS. They use the Unified Extensible Firmware Interface (UEFI), also known as EFI, instead. Have a look at http://en.wikipedia.org/wiki/Unified_Extensible_Firmware_Interface for information on this.


Note that the EFI update you mentioned has modified the firmware on your machine.

Sep 21, 2011 5:09 AM in response to markfromwillaston

Many thanks for the information Markfromwillaston!


I didn't know that, since I am newly "converted" to Mac OS and Apple machines, but I still work on a Windows PC as well. If the EFI is the (almost) equivalent of the BIOS, then it's maybe his fault for the strange behavior of my MBA and not Lion OS.


From what I have found in the web about EFI there's almost nothing, which a normal user can modify. In a traditional BIOS you can adjust very many things. I can only hope that someone from Apple reads the posts in the forum!

Sep 28, 2011 6:29 AM in response to Leon 15

I think I found a solution of the problem! The culprit is the "deep sleep" mode of the MBA. After an hour after closing the lid, the MBA makes an image of the RAM (about 4 GB of space at the SSD) and then turns off completely. After opening the lid the MBA reads this image into the RAM and start the machine - and rapidly heats up.


If you disable the deep sleep following this link: http://pocketpccentral.net/blog/2011/08/02/disable-safe-sleep-lion/


you get these benefits: 1) faster wake up of the MBA after more than an hour of sleep; 2) no heating up of the MBA; 3) you save 4 GB of SSD space, which was till then reserved for the RAM image; 4) no copying of 4 GB of RAM on the SSD everytime you keep your MBA with closed lid for more than an hour.


On the drawback side: 1) maybe a risk, if you have closed the lid of the MBA with a still running programm and if your battery is under 20 % of charge, then you have to start this programm again. However, if you shut down every programm properly before closing the lid, then everything is OK; 2) Since disabling the deep sleep means to constantly give some battery supply to the RAM to keep its state, then you won't be able to have the offered 30 day of stand by. I don't know how many days of stand by you get with deep sleep off.


By the way - I turned the deep sleep mode after two days on again in order to see, if the fast heating up is there. Unfortunately it was there!


Now I have my MBA with deep sleep off and additional 4 GB of SSD space. It is not a bad solution and I think it is even better for the MBA's functionality and stability, but it is a result of strange behaviour of the MBA after EFI 2.1. update. Maybe the next EFI version would fix this issue!

Oct 3, 2011 7:40 AM in response to jonnytabpni

I'm seeing the EXACT same behavior - deep sleep, upon wake up ~80c to 90c temperatures. Going back to sleep fixes it. Restart will also fix it. My machine did not always do this, it was only after applying the 2.1 EFI update.


For those who are not seeing it, you must put the MBA to sleep for longer than an hour. I usually see it after sleeping for about an hour and 30 minutes. It would be great if someone who says that don't see this, could apply the firmware, put their machine to sleep for about 1 hour and 45 minutes, and then wake it up.

Oct 3, 2011 8:38 AM in response to Mike Loiterman

How do we report this to Apple?


My concern is that this appears to be affecting only a few people since there haven't been many posts on this thread, yet it is a real problem for the few of us that are experiencing it. I presume there is no way to roll back the EFI to the previous version, correct?


Like the others above, I can confirm that my problem started after updating the EFI, and it seems to always happen after waking my MBA from sleep.

MBA 13 (new model 2011) heats up rapidly after wake up from sleep

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