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Mr.Green
Feb 7, 2008, 12:32 PM
I noticed this morning that one of my cores shuts down during heavy load. This has never happened on my Macbook Pro. See attached jpg.

Anyone else have this problem?

Is it due to heat?



NAG
Feb 7, 2008, 12:34 PM
What were you doing at the time?

thejadedmonkey
Feb 7, 2008, 12:35 PM
Your MBA is (on average) around 60+ hotter then my MBP is right now. Your fans are also on max... so yes, I'd say that's very possible.

NAG
Feb 7, 2008, 12:36 PM
Remember guys, temperature can be represented either in C or F (or kelvin, I suppose).

Your CPU is running about 20F higher than his is, by the way.

loghyr
Feb 7, 2008, 01:09 PM
Is it due to heat?

What utility are you using to get the temperature and fan speed?

I.e., I figured out how to get the Activity Monitor... :cool:

NAG
Feb 7, 2008, 01:16 PM
Widget called iStat Pro.

loghyr
Feb 7, 2008, 01:27 PM
Widget called iStat Pro.

Sweet, that was painless to install!

Eidorian
Feb 7, 2008, 01:36 PM
There was a knowledge base article about the MacBook Air shutting a core down to prevent overheating but it's no longer online.

MacBook Air: 3D graphics applications less responsive when CPU has been in heavy use for prolonged period (http://docs.info.apple.com/article.html?artnum=307297)

http://www.google.com/search?client=safari&rls=en-us&q=MacBook+Air:+3D+graphics+applications+less+responsive+when+CPU+has+been+in+heavy+use+for+prolonged +period&ie=UTF-8&oe=UTF-8

noodle654
Feb 7, 2008, 02:19 PM
I noticed this morning that one of my cores shuts down during heavy load. This has never happened on my Macbook Pro. See attached jpg.

Anyone else have this problem?

Is it due to heat?

Could be the first major MBA problem?

I must say that 158* is pretty high...call up Apple.

Consultant
Feb 7, 2008, 02:36 PM
What were you doing at the time?

He is using it to encode movies. See ffmpeg/VisualHub

In addition, he has apps open for torrents, music, video(s), and browsing web.
Well, at least he's not trying to play Crysis at the same time. =p

Translation = full CPU usage = heat
Might want to get a laptop cooler...
I am thinking about building one with 120mm quiet fans instead of a store bought that are fairly loud.

Eidorian
Feb 7, 2008, 02:37 PM
Could be the first major MBA problem?

I must say that 158* is pretty high...call up Apple.I'm sure you've never seen a Macbook or Mac mini hit 190 F then.

TEG
Feb 7, 2008, 02:42 PM
Most systems are not suppossed to get above 70c. The reason for the core shutdown is three fold, 1) to reduce heat, 2) to save power when not needed, 3) to save battery life when unplugged.

You should be able to deactivate this "feature" by selecting "maximum" as your processor speed in the energy saver preference pane.

TEG

steffi
Feb 7, 2008, 04:29 PM
Well you're running VisualHub when this happens right so it's not all surprising that that's happening really.

Most systems are not suppossed to get above 70c. The reason for the core shutdown is three fold, 1) to reduce heat, 2) to save power when not needed, 3) to save battery life when unplugged.

You should be able to deactivate this "feature" by selecting "maximum" as your processor speed in the energy saver preference pane.

TEG

mactastic1971
Feb 7, 2008, 04:35 PM
I know the real memory looked small but there seemed to be ahelluva lot of virtual memory. Could that be swapping in and out causing IO wait or something ???

NAG
Feb 7, 2008, 04:47 PM
Nah, just because there is a lot of virtual memory allocated doesn't mean there is a lot of swapping going on. We'd have to see his memory tab to know more.

mactastic1971
Feb 7, 2008, 04:50 PM
Nah, just because there is a lot of virtual memory allocated doesn't mean there is a lot of swapping going on. We'd have to see his memory tab to know more.

Its just I've seen issues in linux where it automatically caches virtual memory for the last used applications and it will keep doing this until all the real memory is used. Then if the kernel needs to do something, one of my other cpus can drop out...

Again... linux... not osx...

NAG
Feb 7, 2008, 04:54 PM
Yeah, I was just commenting that we need more information to say anything conclusive about that.

JasonBourne9
Feb 7, 2008, 05:11 PM
Hmm... just discovered that watching streaming 720p episodes of Lost from the ABC site overloads the processor and causes intermittent core shutdown. Annoying because it then gets all choppy and unwatchable.

That's a shame.

Mr.Green
Feb 7, 2008, 09:08 PM
I was primarily encoding video using VisualHub for my iPhone, and downloading something with Transmission. The computer was sitting on a marble table in my hotel room.

On my Macbook Pro, I am able to run the processors at 100% all day long encoding video. The fans would spin up at max and be very noisy, but I could do it if I wanted and the cores have never shut down like this. My first Macbook Pro, the core 1 duo, would sometimes even reach 85-90 degrees C / 185-194 F. My rev 2, Macbook Pro doesn't ever get that hot.

The processor on my Air almost never even reached 100%. I would have expected in the Air, Apple should have tested it and designed it so it could run at 100% without overheating and triggering a CPU shutdown.

I love my Air, but I think this is a mistake. Apple does like to push the thermal envelope all the time and I think they went a bit too far. Hopefully there would be a software fix for this.

steffi
Feb 7, 2008, 09:56 PM
Anybody installed Menu Meters on the air so you can see this activity in the menu bar all the time? That would be rather revealing.

I was primarily encoding video using VisualHub for my iPhone, and downloading something with Transmission. The computer was sitting on a marble table in my hotel room.

On my Macbook Pro, I am able to run the processors at 100% all day long encoding video. The fans would spin up at max and be very noisy, but I could do it if I wanted and the cores have never shut down like this. My first Macbook Pro, the core 1 duo, would sometimes even reach 85-90 degrees C / 185-194 F. My rev 2, Macbook Pro doesn't ever get that hot.

The processor on my Air almost never even reached 100%. I would have expected in the Air, Apple should have tested it and designed it so it could run at 100% without overheating and triggering a CPU shutdown.

I love my Air, but I think this is a mistake. Apple does like to push the thermal envelope all the time and I think they went a bit too far. Hopefully there would be a software fix for this.

Eidorian
Feb 8, 2008, 10:41 AM
Seems like utilizing the processing power of the dual core processor is going to make it a single core anyways.

Hopefully there would be a software fix for this.Hopefully it won't melt your laptop. Then again Apple changed the thermal tolerances and fan speeds for the G5 in Leopard.

*cough*Thicker laptop*cough*