Macbook Air overheating results in 1.2 GHz CPU

[BongoBanger]

Why do you all assume this is due to heat? It's standard to lower clock frequencies as part of power management. That's obvious from those that see the CPU cycling down when the part isn't hot.

Not when they're being stressed at 100% load it isn't.

 

[NC MacGuy]

Why do you all assume this is due to heat? It's standard to lower clock frequencies as part of power management. That's obvious from those that see the CPU cycling down when the part isn't hot.

I assumed it wasn't because first screenshot showed plugged-in which is usually indicative of better performance settings.

Who knows?

 

[SodiumBenzoate]

Why do you all assume this is due to heat? It's standard to lower clock frequencies as part of power management. That's obvious from those that see the CPU cycling down when the part isn't hot.

Power management lowers the frequency when there's no significant load, not when the CPU is working hard..

 

[bcaslis]

Power management lowers the frequency when there's no significant load, not when the CPU is working hard..

I understand that, but I think the two are being mixed in some of the posts here. There also have been other posts in other threads about the MBA using much more aggressive power management than other Apple laptops, there was specifically an update to Parallels or Fusion (don't remember which one) specifically because of this.

 

[purplewarlock]

The reason I think heat is related is I think this is the reason why a Core shuts down and in some cases extreme CPU/GPU throttling occurs. Why else would the system throttle CPU/GPU besides heat? If anyone has another reason (page swapping is the only I can think of, though with 2GB I don't think that is the issue), there might be other possibilities.

Another interesting thing I found relating to this is World of Warcraft plays extremely well on OS X on Air for about the first 10 minutes. Performance is great. Thus the GPU is physically capable of performing at a fast level. It's only after about 10 minutes or so where it slows down 50-90%.

All of this indicates some sort of bug in the OS X heat control mechanism, or another OS X bug, or excessive page swapping or something like that, or a Mac specific device driver bug, or perhaps a Mac specific OpenGL bug. I don't think there is anything inherently wrong in OpenGL or the underlying UNIX architecture that would explain this.. I think it is Apple specific code that causes this behavior. The good news is if they actually care enough about this to find and fix it, it would be a free software update that doesn't cost any money as opposed to a hardware issue which would require you to purchase the next generation of Air for the fix.

My main point is the Air hardware is easily capable, as shown by Windows via Bootcamp, to sustain a dramatically higher graphics throuput than when run on OS X. I could understand a 10-20% difference as pretty minor but I'm seeing about a 50% or greater difference between the two operating systems, this indicates something more along the lines of a serious defect to me than just the normal differences between the platforms.

 

[Beliyaal]

The same problems exist in Windows, it's just generally that things are more effectively written in Windows, taking less CPU and thus causing less heat. (I.e Direct 3D instead of OpenGL, and more optimized video codecs).

I have done some more tests with the Apple CPU power management kext unloaded and it seems that the throttling is initiated by a source external to the processor. What tripps the thermal management is either PROCHOT# or FORCEPR#. This means an external chip on the motherboard is asserting these pins on the processor. So either external thermal or power management.

The most likely reason is that the PMU or SMC is detecting the power draw of the processor and tries to keep it below a certain level.

 

[hotdamn]

Beliyaal, try the test from battery.
Seriously, mine only gets weird when it's plugged into the wall.

 

[Beliyaal]

Beliyaal, try the test from battery.
Seriously, mine only gets weird when it's plugged into the wall.

The latest tests was run from battery. I also tried undervolting the processor, and I was able to keep it at 1.4 GHz for about a minute under full load, but eventually it went down to 1.2 Ghz.

 

[ttpjd1]

Just another statistic...

Hi Guys,

FYI, I have a MacBook Air 1.6/80HDD. Running some scientific calcs in Win32 app under Parallels and XP (installed on the Boot Camp partition).

As an aside, prior to the MBA-specific Parallels patch mentioned above, I had loads of (maybe 100?!) kernel panics. Are there others here who are now able to say 'You must now restart your computer.' in 5 different languages? These forced me to restart both the Mac and XP every time. Not my idea of fun. But I thought my troubles were gone with the Parallels patch (once I was finally able to track it down).

Now I have the overheating issue. The MBA runs for five seconds (ish), freezes for seven (ish, it's not consistent), and my calculations now seem to be taking MANY times longer than they should.

It's intensely frustrating.

Running MSR tools shows the temp going over 90 deg, and both cores dropping to 0.8GHz (is that a record so far on this Forum?!) and that's even BEFORE the machine gets hot enough to start freezing!

So even when the machine appears to be running properly, I guess I'm probably only getting 50% of the performance I expect. Factoring in the freezes, I guess that means my calc is probably running about 20% of the speed it should be (and that feels about right).

FYI, I'm seeing the 0.8GHz with the machine very carefully elevated on a Griffin iCurve, and placed in the coolest part of our house!

Not a happy bunny...


Phil
Marlow, UK

 

[ayeying]

I don't see what you guys are fussing about anymore. I've used to be in your position, pushing the air to max and beyond. Making the system overheat or find some way to shut a core down and such. After a while, I think, am I testing this computer or actually using it.

Right now, I can run 2x virtual machines (ignore the fact my heatsink is modded) itunes, firefox w/ 5+ tabs (mild flash ads), iChat, Mail.app, and iCal all at once without the fans going above 2500rpm.

> How I do it you might ask?

Well, besides the fact I'm running at 0.9V on my cpu, I am also only running it at 800MHz.

> Why run it at 800MHz? Isn't that slowing your entire system down?

Why? I don't need the extra speed. Even hooked up with a second monitor, the virtual machines are normally just idling. cpu usage might go up because of the lower speed but heat doesn't. At 800MHz, the 2500rpm fan is more the capable of cooling the system down even at 100% load (not indefinite, approx 15-20 minutes before fans require spinning up)

Yes, it does slow the system down, but in my experience, its not slow for what I normally do. I surf online, watch a few youtube videos, play iTunes, chat with a few ppl on iChat w/ webcam... thats about it at home. At work, I have dreamweaver (i know, it sucks) and SQL Developer opened along with iTunes and iChat. Thats about it. Nothing here is really demanding on the CPU for speeds above 800MHz. Everything still opens just as fast max cpu speed. OSX is really optimized here, thats what really counts.

In the several days I've used this setting, I was amazed that hte system was extremely responsive, as responsive as my dad's iMac (2.4ghz, 4gb ram) in opening programs, viewing files, web surfing and such. The first few days, I did not know I had the cpu locked at 800MHz. When I found out, I couldn't believe it.

> Sounds like 800MHz is enough for you, but your cpu is capable for 1.6GHz.. what do you do with that extra speed available?

Think of it like a car. The car engine has a high rev capability (I have 7100rpm) but in normal driving, do you rev that high? Many average drivers only do 2-3k rpm. Its the same concept here in using the macbook air for me. I have the power, I'm just not using it when I don't need to. There are times where I do need the 1.6GHz, for example when I convert AVI files to MP4 for my iPod using iSquint. At 800MHz, it'll take about 30 minutes for a 350MB file. At 1.6GHz, I'm at 10-12 minutes, a lot faster. At this point, I turn on throttling. After I;m done, I turn it off, reducing heat, noise, power (I'm on battery nearly 2-3 times a day, using up 60%+ charge each time).

I'm not saying this is right for everyone, but this is what I'm experiencing and how I'm using my macbook air right now.

 

[sir. mac]

So even when the machine appears to be running properly, I guess I'm probably only getting 50% of the performance I expect. Factoring in the freezes, I guess that means my calc is probably running about 20% of the speed it should be (and that feels about right).

Not a happy bunny...


Phil
Marlow, UK

As somebody said, you don´t need all the power most of the time. What really could help you is to undervolt the cpu. It would, in principle, make the CPU stay at higher speeds for longer time. Additionally with the program Coolbook (10$@coolbook.se) you could force the cpu to stay on the maximum setting. I think there is a safety margin, so that the cpu automatically drops if heat goes up to dangerous levels. But if you also undervolt (also possible with Coolbook), you would be able to make it stay on the highest cpu, probably indefinite.

My cpu now stays at 85 celcius on maximum load at maximum cpu-speed. But most of the time I stay at 1200mhz clocked @ 0.9 (general working temp with Word 2004 and safari on is now around 50 celcius, and it used to fire up the fans).

essentially I saw a 10 degrees decrease after using coolbook and undervolting it. Next step is to open it up and reapply the thermal paste to get it down another 4-5 degrees.

Best of luck!

 

[173080]

I'm using CoolBook to run my MBA at 800Mhz permanently. I was running 2x yes > /dev/null. In normal use the temp is generally less than 45C.

I code on the air and send all the heavy processing to a pair of Xserves so 800Mhz is more than enough. In fact, I couldn't really tell the difference between 800Mhz and 1.6Ghz.

 

[ExcelonGT]

Ayeying, Great explanation.

I was just about to post the "car engine" analogy. you beat me to it!

there definitely was something wrong with the cooling capability of the MBA. Reapplying the thermal grease seems to have resolved that issue. I am pushing my MBA just as hard as you without the problems I was experiencing before "fixing" the thermal problem.

 

[macsmurf]

Well, I am most impressed with your dedication to the company. I, for one, totally disagree with you. What Apple advertises is a 1.6-1.8 GHz CPU and if this in unattainable for whatever reason, the only ethical thing for Apple to do is tell its customers about it. IF these numbers hold for a majority of the Macbook Air, that would seem to suggest that Apple have been willfully withholding information from its customers, and I am not the slightest bit impressed by this.

Someone should replicate this experiment from the ground up, and if the evidence holds up, Apple should either replace all the faulty units and/or offer the information up front on their website along with a healthy discount.

Although Apple do a lot of things right, false advertising is not something I'm prepared to accept from any company.

Again, this is under the assumption that the evidence is solid, which it is not at this point, but it ought to be taken seriously.

 

[alphaod]

What I'm interested in now is if all Air:s have these problems. I have put the application that should be considered in Alpha state on my homepage: MSR Tools

I ran it on my MBP. Very nice app.

Does your app affect the fan control? Cause my fans kicked in max when it was 85 before. Now it's around 95 and it's kicked max yet...

I don't see what you guys are fussing about anymore. I've used to be in your position, pushing the air to max and beyond. Making the system overheat or find some way to shut a core down and such. After a while, I think, am I testing this computer or actually using it.

...

> Sounds like 800MHz is enough for you, but your cpu is capable for 1.6GHz.. what do you do with that extra speed available?

Think of it like a car. The car engine has a high rev capability (I have 7100rpm) but in normal driving, do you rev that high? Many average drivers only do 2-3k rpm. Its the same concept here in using the macbook air for me. I have the power, I'm just not using it when I don't need to. There are times where I do need the 1.6GHz, for example when I convert AVI files to MP4 for my iPod using iSquint. At 800MHz, it'll take about 30 minutes for a 350MB file. At 1.6GHz, I'm at 10-12 minutes, a lot faster. At this point, I turn on throttling. After I;m done, I turn it off, reducing heat, noise, power (I'm on battery nearly 2-3 times a day, using up 60%+ charge each time).

I'm not saying this is right for everyone, but this is what I'm experiencing and how I'm using my macbook air right now.

Like the analogy up to a certain point. I think many people are arguing here and I would too is that why did Apple design a computer at 1.6/1.8 when it can't perform at that speed? It's like putting a Bugatti Veyron engine into a E-class Mercedes. There is a reason the Bugatti has 10 radiators! Same thing with the MBA; Apple tried to do what they though no one else could do and they did it. Maybe there is a reason everyone else is using LV processors?

 

[ayeying]

Like the analogy up to a certain point. I think many people are arguing here and I would too is that why did Apple design a computer at 1.6/1.8 when it can't perform at that speed? It's like putting a Bugatti Veyron engine into a E-class Mercedes. There is a reason the Bugatti has 10 radiators! Same thing with the MBA; Apple tried to do what they though no one else could do and they did it. Maybe there is a reason everyone else is using LV processors?

Ya, the analogy works to a certain point. I understand in the computer business, advertised speed matters. Unlike in the car market, a car has 200 hp but you need to rev the engine to maybe like 5000 rpm to achieve the power output.

Apple isn't entirely lying. The system is capable of achieving those speeds. The MacBook Air 1.6 or 1.8GHz models is capable to run at those speeds, just our problem here is the heat.

The heatsink, in my opinion is the biggest problem. A flat aluminum piece (thats flexible btw) is not enough to cool a system. If the heatsink were to be redesigned with more surface area, more mass, slightly larger (remember it needs to cool the CPU, Northbridge(?) and Ram) it might be a tad better for all of us. Copper helps too, but I think apple's idea here is to make the system using nothing but aluminum.

 

[macsmurf]

Apple isn't entirely lying.

What does that mean? Either they are or they're not. The CPU in a laptop should be expected to function under stress at its maximum rating continuously for months or even years. This is an entirely reasonable expectation, because all non-faulty laptops ever build can do this (AFAIK). Assuming this is not a hoax/bad programming and it's a problem for the majority of Macbook Air, Apple would know about it. When they fail to share that knowledge with the consumer, leaving them with the misconception that the laptop can actually run at 1.6/1.8 for more than a moment under stress, they are lying by omission.

 

[fuzzielitlpanda]

my mba is currently running at 1.6ghz with a cpu temperature of 45C on idle. the mba is very much able to run at advertised speeds. however, it seems like everyone is having different results when it comes to cpu temperature.

 

[daneoni]

The Air is all about compromises, this seems to be just another one of those compromises.

 

[macenforcer]

All apples current laptops are in the same boat. Not a single one of them is designed to deal with heat.

I have been testing all the apple laptops for months now and all of them exhibit the same problems. First of all the fans run non stop at 1800rpms minimum. That is bad right there. Secondly I ran simple tests on all of them. I tested ichat, youtube, and HD video playback and every machine reved up the fans to max. Macbook pro took a little longer to do this but still did it.


NOW. I got a 2.5ghz penryn Lenovo T61 in front of me that runs with NO fan being on. When using skype NO FAN turns on. WHen doing HD video the T61 takes a few minutes then the fan comes on but its very quiet.

Apple chooses to design there machines to look good, not work good. Its sucks.

 

[stakis]

Hi, I'm running Coolbook and I don't have any problems... I noticed that when I was doing some tests to see if Coolbook was actually doing anything for me that the cpu clock speed "according to coolbook" was dropping down to 1.2 without the coolbook program enabled.... one I installed this program and ran your application I'm getting 1.6 ( I have the 1.6/80) with 2 instances of 'yes' for about 10 minutes....


just thought I'd share...

coolbook really is the Air's best friend!!

 

[ayeying]

The Air is all about compromises, this seems to be just another one of those compromises.

I don't think many would agree to compromise on a CPU speed that differers from advertised.

All apples current laptops are in the same boat. Not a single one of them is designed to deal with heat.

I have been testing all the apple laptops for months now and all of them exhibit the same problems. First of all the fans run non stop at 1800rpms minimum. That is bad right there. Secondly I ran simple tests on all of them. I tested ichat, youtube, and HD video playback and every machine reved up the fans to max. Macbook pro took a little longer to do this but still did it.


NOW. I got a 2.5ghz penryn Lenovo T61 in front of me that runs with NO fan being on. When using skype NO FAN turns on. WHen doing HD video the T61 takes a few minutes then the fan comes on but its very quiet.

Apple chooses to design there machines to look good, not work good. Its sucks.

Do remember those laptops use a slightly different heatsink design. I remember from my Dell 8600 notebook PC, the fans DID NOT turn on at all until hitting 65 deg C. Aside from the ugly case design, that laptop was the best PC laptop I've used.

Apple laptops require a fan to be running at all times because of how they designed the heatsink. From my understanding, the air and macbook cools both the CPU and the chipset, not just one item. On the pro, its the same heatsink for the CPU, GPU and Chipset. I haven't taken apart the T61 but I don't think its CPU heatsink comes in contact with any other heatsinks in the system. It may share the same fan, but I don't think it'll be apart of the same heatsink (someone prove me wrong?)

Now, having a laptop that has its fans running, at a near silent level, whenever you have the system on its hardly a bother imo.

Apple laptops, aside from the air, has been designed pretty well to deal with heat. You don't see the MB or MBP users complaining as much as us about heat problems. Other laptops are in a similar boat. Heat is something that affects ALL laptops, not just the macbook lines. If you have a slightly thicker, heavier and larger laptop, your heat is more easily controlled. If you have something like an ultraportable, aka the air, or any other ultraportable, you'll see heat is an issue and is a primary reason why other computer makers use ULV cpus or the other stuff to keep CPU temps down.

 

[macenforcer]

I haven't taken apart the T61 but I don't think its CPU heatsink comes in contact with any other heatsinks in the system. It may share the same fan, but I don't think it'll be apart of the same heatsink (someone prove me wrong?)

The T61 heatsink is all copper and covers everything. The GPU, CPU and northbridge. Its quite awesome. Fan never comes on.

I'm quotin here:

"All these changes account for the dramatically lower GPU temps at idle, even with the higher-end GPU that T61p has in comparison to the T60. "

"Another aspect some might notice is how quiet the new T61 series is under load. At first I was thinking it was a new fan design, but playing with tpfancontrol I noticed you only have 3 fan speeds instead of 7 on the T60. It is quieter under high load because the fan is limited to ~3300rpm, whereas the T60 can go upwards of ~4300rpm. Less noise yes, but also less peak airflow. Speeds 1-3 are roughly the same noise level, but the T61 (with its newer heatsink design) spends more time without the fans on at all."

 

[ayeying]

The system is 1.26" thick too 😀

But seriously, if apple used copper, it could've saved us a lot of trouble. Anyone wish to take up the challenge to create a copper heatsink for the air? I could get my dad to make one for me (since he works as a machinist) but he'll start questioning why I need a copper piece designed this way.

 

[alphaod]

The T61 heatsink is all copper and covers everything. The GPU, CPU and northbridge. Its quite awesome. Fan never comes on.

I better hope they upgrade the cooling in the T61; the T60 doesn't blow the heat out well enough.

The system is 1.26" thick too 😀

But it's built like a tank.