Overheating to 90C on Macbook

[Jeff Gilchrist]

Originally Posted by Prime95

My laptop did develop some kind of problem over time and the chip ran at 99C forcing the OS to underclock the chip. Thanks to AppleCare Apple fixed the problem.

What kind of problem was it? I noticed that mine are at 99C as well.

Jeff.

[kaffikanne]

If I run Prime95 on my macbook pro summer 2009 15" it rockets up to 108 degrees according to iStats. The fans do not increase from 2000 rpm. But using smcfancontroll I can force the temperature down.

[mdettweiler]

Originally Posted by Jeff Gilchrist

What kind of problem was it? I noticed that mine are at 99C as well.

Jeff.

Yowch! That sounds awfully high to me, laptop or desktop. Unless some newer CPUs are designed to run at those higher temps or something...what kind of CPU is it?

[retina]

Originally Posted by mdettweiler

... what kind of CPU is it?

It doubles as a kettle. You know, for boiling water. Haven't you always wanted a computer that makes your coffee also?

[Prime95]

Originally Posted by Jeff Gilchrist

What kind of problem was it? I noticed that mine are at 99C as well.

I'd have to look at the repair paperwork. I recall they replaced a couple of parts - one had something to do with Thermal management.

If you are running at 99C are you also getting downclocked? I used CoolbookController to display the cpu speed. The free version will do this.

I replicated the problem for Apple by opening two terminal windows and typing "yes > /dev/null".

@mdettweiler: 99C is the max temp for the mobile Core 2 Duo based on the Penryn (45nm) design.

[Jeff Gilchrist]

Originally Posted by Prime95

If you are running at 99C are you also getting downclocked? I used CoolbookController to display the cpu speed. The free version will do this.

Yes it is a 45nm Core2 CPU rated at 2.5 GHz.

It seems I have a temperature difference in monitoring apps. I'm using Temperature Monitor 4.8 which is reporting CPU A Temperature Diode at 99C and CPU Core 1 and CPU Core 2 at 90C. Now with CoolBook installed it is reporting 85C (not sure exactly what it is measuring).

But they both report the CPU is running at 2.5GHz so it looks like no throttling is occurring which makes me believe the 86C temperature more and not the higher value. Still, 86C seems hot but within spec I guess.

Jeff.

[mdettweiler]

Originally Posted by Jeff Gilchrist

Yes it is a 45nm Core2 CPU rated at 2.5 GHz.

It seems I have a temperature difference in monitoring apps. I'm using Temperature Monitor 4.8 which is reporting CPU A Temperature Diode at 99C and CPU Core 1 and CPU Core 2 at 90C. Now with CoolBook installed it is reporting 85C (not sure exactly what it is measuring).

But they both report the CPU is running at 2.5GHz so it looks like no throttling is occurring which makes me believe the 86C temperature more and not the higher value. Still, 86C seems hot but within spec I guess.

Jeff.

Aha...maybe it's accidentally reporting the maximum temperature as the "real" figure? I've noticed that applications like that tend to get mixed up in that regard; for example, a friend of mine has some machines running Linux that always have the CPU temp and mobo temp swapped. We noticed because the CPU temps just seemed way too low to be reasonable, and the mobo seemed to be boiling (but well within normal range for a CPU).

[Sve]

Thank you very much for the information about overclocking. I tried to learn more about that but couldn't find much on whether or not a program could do it on its own. I appreciate your explanation.

The vents are not being blocked by any objects outside. The machine is about two years old though so maybe dust has gotten inside. I'll bring it to the store some time soon to see if they can check.

How do I turn on the throttling? Are TF, LL, and P-1 different types of calculations? Do they affect the power used? How do the fan control programs work?

Maybe I should just get my old desktop computer running again and let that get at hot and noisy as it pleases...

Also, I just got the following emails from Apple.

The original email that the guy on the phone sent to the engineering people:

Configuration:
Macbook 13/2.0/2x512/80/combo:white USA
10.5.2
Running Mersenne.org Simular to the folder@home program

Troubleshooting Steps and Workarounds:
Mersenne.org program was installed and then ran when it ran it started over heating on the computer.
Computer was running at 90ºc when cx first ran the widget.
Now it is running at 55ºc after the application is Quit.
Simular to the folder@home program

Actions Requested and Additional Comments:
As soon as quitting the program her computer started cooling down sounds to me like the program over clocked the processor even if only on accident. anything we can have her do beside uninstall the program and tell her to not use it?

The response from the engineering people:

Hello,

Thank you for your escalation. I don't believe the app did anything to the system to overclock the processor or the like. The app is doing seriously high end math calculations. This type of work will use the processor at 100% constantly and will thus cause the system to heat up quite a bit.

While there is not anything directly wrong with using an app like this, the temp levels are still within safe levels as it's the chip that is at that temp not the external case, I would recommend if they are going to do this they make sure the system is in a location that allows for the rear vent to be clear and for good airflow around the bottom of the system.

Thank You,

Michael Netting
Portables/CPU Software Site Support Engineering

[starrynte]

How do I turn on the throttling?

If you are running on a laptop or in a hot room and you want to slow the
program down to reduce heat, then you can add this line to prime.txt:
Throttle=n
where n is the percentage of time the program should run. For example,
Throttle=40 means the program will run 40% and be idle 60% of the time.

Are TF, LL, and P-1 different types of calculations?

Yes; TF is trial factoring and (the TF assignments primenet assigns currently) requires the least computing power
P-1 is another way of factoring and if stage 2 is run requires the most memory.
These two tests are to easily remove candidates for the (relatively) costly LL test, which is the actual test to see if an exponent is prime. There are two primenet assignments of this type: double-checking, which re-runs the test on assignments already done, and first-time tests, which naturally takes the most time.

I'll leave the other two questions for others to answer since I have to go now.