Macbook Air owners know what I’m talking about – the dreaded core shutdown. When the MacBook Air gets too hot, there is a built-in thermal shutdown feature that turns off one of the two cores in the Core 2 Duo Intel processor found in the MacBook Air. The problem is that one of the cores often shuts down at temperatures that shouldn’t be worthy of a thermal shutdown. If you want to test this out, one easy way to get the MacBook Air to shutdown a core is to connect it to a larger external display and use it normally or watch some HD video. This stresses the GPU, which is on the same heatsink as the CPU, and initiates a core shutdown.
Core shutdown has become an inevitable part of using the MacBook Air as my primary machine, but I think I found a solution while Googling away in sheer core shutdown annoyance earlier today. Undervolting is apparently the answer. Using an application called CoolBook I was able to set some processor throttling settings with speed and voltages.
After I purchased a license for CoolBook so that I could change CPU speed and voltage, I created a few throttle points and rebooted. Undervolting essentially runs less juice through the CPU and combined with various processor frequencies you can set, the CPU produces less heat. This means no more core shutdown and longer battery life at almost no perceptible expense. Yeah, undervolting does mean the processor will be running slower but I set a throttle point of my full 1.6GHz for when it’s needed. When it’s not, such as when I’m simply web browsing, the CPU speed lowers.
However, I have noticed that when using CoolBook the MacBook Air is allowed to get very hot (75+ deg C). Just keep an eye on your temps if you do anything extremely processor intensive. I use smcFanControl.
Rob Randtoul has the specifics for configuring CoolBook for the MacBook Air. It worked for me.
Do you have a MacBook Air? Have you had to deal with core shutdown? Core shutdown usually isn’t a problem for me unless I am connected to my 24-inch monitor or watching HD video on the internal display.
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They call it “bleeding edge” because it hurts ;-)
Love Apple to death but I never buy their v. 1.0 products.
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Hmmm. I hope that by the time I get a Macbook Air, there’ll be either a better, newer version of the one you have now, or a newer, better, thinner, slimmer (cheaper, maybe?) model.
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add: wow. two posts in two days. you sure made up for lost time. :-)
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Paul,
I had the same problem with my MBA. Of course, when I went to the Genius Bar to describe and try to re-create the core shutdown, it ran flawlessly. I found CoolBook shortly thereafter and haven’t had a core shutdown since.
I have noticed that when the computer is plugged in it runs really hot. Sometimes up to 90 degrees.
Anyway, great post! I wonder if Apple will have any firmware updates in the future to address the problem.
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The latest MacBook Air firmware update seems to have sorted the problem. I am not having any more core shutdowns (as I used to have them very often with multiple firefox tabs open). The CPU temperature has come down from 80 to 50 degrees. I hope this lasts. Otherwise extremely happy with the Air.
The core shutdown problem started about three or four days after I got my MacBook Air around two weeks ago. I would start playing videos on YouTube and the second core would shut down, locking up the first core and making the cursor very sluggish.
I since have purchased CoolBook and using the same settings I no longer have to deal with the core shutdown issue. Of course, I hope this is fixed officially by Apple sometime in the future.
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Thanks for the tip. I’m planning on getting a new Mac. This will prevent some frustrations!
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I will look into Coolbook
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I’m curious about an update to this post. Did a firmware update fix this, or is this still a problem? I’m considering buying a MBA or a MBP to hook up to a 24″ monitor. I don’t want the Air if I can’t watch movies on it, have to buy CoolBook and always have it running, or if it gets very very hot.
Any word on what’s happened with this? Thanks!
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@Blake – yeah this is still an issue. Although no real complaints from me after CoolBook. :-) I always have my MBA hooked up to my 24-inch and it works fine for that and watching movies, with CoolBook. As long as they aren’t 720 or 1080 you’re fine.
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Blake- let me know if you’re interested in a MBA. I’ll sell you mine… I’m going back to a MBP.
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Spoke with AppleCare about MB Air “stalling” when in single core mode. He had me do a power management reset by shutting off the computer, holding SHIFT-CONTROL-OPTION and firmly pressing the power key. Nothing will happen, no tone or flash. Just restart. Single core mode is much less frequent, only during heavy stress and only momentarily. Programs are responsive while in single core (much more than before the reset when the entire computer would beach ball). SO far, it’s seemed to do the trick and I’m back to loving my Air. He (Applecare dude) sad they expect to have a more elegant fix in 10.5.4. Thanks Applecare dude.
Got my 3rd Macbook Air today from Apple – all of them exhibited the same core shutdown problem. I purchased the coolbook to give it a try – because I really like the Air. Paul is right that the little coolbook utility prevents the Air from shutting down one of the cores. The problem is though that it switches off the temp limit as well. With the settings above my Macbook Air goes to sleep automatically after about 5-10 minutes of importing AVCHD video (even though the sleep is disabled). The Macbook Air sits on a straight wooden table in a well ventilated room. The CPU temperature goes above 100 degrees Celsius – which is I think unacceptable. Looks like the fan in Air can not keep the CPU cool while performing more demanding tasks. Looks to me like a design flaw and even this 3rd Air goes back to Apple – and I want my money back.
Will probably wait for a 2nd generation of Macbook Air until this gets fixed. The desing is lovely – yet the functionality kinda sucks.
“They call it “bleeding edge” because it hurts ;-)
Love Apple to death but I never buy their v. 1.0 products.”
Remember the first PCI Macs in 1995? These shipped with bleeding edge system software. The part that had the most problem was a then-bleeding edge networking software called Open Transport, and this was probably much worse than this issue. System 7.5.3 and the Open Transport 1.1 shipped with it fixed most of the problems.
I admit my Macbook Air has not suffered core shutdown as of yet, although it is used for travel only and only handles word, excel and some itunes music and movies. Even on hot days it hasn’t had any issues, my MBP gets the most use and despite a hot case it performs flawlessly.
I will give my MBA a good work out and see if I get a core shutdown. Be interested in seeing what Apple do about this issue.
I have a macbook air and to date have never experienced core shutdown, I even tried rigging it up to a 22″ monitor while, running AOL, firefox and iTunes running a video. It was also running a 4 port USB hub and backup drive using time machine.
The CPU got warm about 68-70 degrees C, but it didn’t crash or lockup, it was noisy but at least it was working. I only noticed it was a little slow in use that was all. Once time machine finished the temp dropped to 58-60.
So far I have been very impressed with the macbook air, it’s light and very portable. I have a large Macbook Pro for main work but the Air is ideal for travelling with. I think for now I will leave the machine as it is, it’s working great for me.
apple finally addressed this issue! there is a software update 1.0 for macbook air owners. please be sure to inactivate coolbook controller if you use it and restart your macbook air before installing. from apple note
“Third-party software that modifies processor operating characteristics such as frequency and voltage is not supported and should be removed before installing this update.”
more on update here. http://www.apple.com/support/downloads/macbookairupdate.html
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@geminiimatt – I tried the update and while a core did not shut down, I did still experience the kernel_task issue where that process uses all system resources after initiating several processor intensive issues. I have gone back to using CoolBook and it works fine as usual (even with the new update).
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@stammy are you still running coolbook after the new update and not having any problems? I am holding back on the update to make sure people don’t report problems using coolbook w/this update. thanks.
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I tried but it doesn’t work after firmware update :(
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@blake http://paulstamatiou.com/2008/05/11/putting-an-end-to-macbook-air-core-shutdown#comment-167122
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@stammy thanks. just making sure it’s still working fine a week later.
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This article is the only way to fix the damn air from locking up! Love it or hate it was burning my legs and it would crash skype video after 10 mins too…
I have the 1.8GHz version, here are my settings:
Adapter:
800 / 0.9000
1200 / 0.9000
1400 / 0.9000
1600 / 0.9375
1800 / 0.9500
Battery:
800 / 0.9000
1200 / 0.9000
1400 / 0.9000
1600 / 0.9.375
(I left out the 1800 setting as it saves battery life and I tend not to use CPU intensive apps. I guess you could go further and drop the 1600 too?)
Throttling: Medium
Temp: 75C
I found that setting the temp lower than 75 made the processor run a lot slower to keep cool. Without the temp control it will run at 1800 all the time but it does stabilise at 91C which if nothing else makes the air too hot to hold.
I’m now able to run skype full screen and watch video and it never locks up….
Cheers,
Matthew
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Same problem with two 1G MBAs. I stumbled upon a solution without quite understanding why. I only knew that the worst-offending MBA was a water-damaged one I re-built. For various reasons I was concerned about the heat sink’s ability to cool this one. I installed “SMC Fan Control” on both computers and have not had a problem since. I’ve kept the rpm minimums at about 3900 minimum.
I just got a $999 refurb MBA. It seems to get hottest when you use it while it is charging. I got my voltages down to .90 at all speeds except 1600, which needed .9125. People should understand that undervolting does not reduce performance. Apple sets the voltages to what Intel says the chip needs. Intel tells Apple what the worst case voltages are. In most cases, the chip can run at lower voltage, which reduces heat output. The other fix you can do to a MBA is remove Apples over zealos application of thermal compound to the CPU and GPU and apply a more correct amount. While this won’t actually make your laptop cooler, it may allow the cpu to more efficiently dissapate heat, allowing it to run without the core shutdown problems. I have not attempted this, but it sounds like a fun project :)
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After months of searching for a solution for the Kernel_Task problem in my MBA I tried the CoolBook software given the increasing number of people who tried it and worked for them and… it just works. Just installing it without changing any of the default values solved the problem. I was facing this problem every time I run a 1080p video on my MBA. First I thought that the video processor is not capable or running such high resolution video but it did after installing the software.
It is clear for me that the problem is not overheating since I was getting this problem with temps in the 60s C. My only interpretation is that CoolBook replaced a faulty processor managing firmware. Still to my surprise why Apple didn’t solve this problem yet !
Just like Amr said “Just installing it without changing any of the default values solved the problem”
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