GPU diode temperature sensor

Question

Level 1

5 points

GPU diode temperature sensor

I use iStat to keep an eye on the temperature of my macbook pro.

I noticed today that the temperature of my gpu diode dropped to -128 degrees Celsius. I updated iStat to version 2.0. Then I noticed that GPU diode does not even show up in the menu. Therefore I downloaded Temperature Monitor and the GPU diode does not show.

I can still see the temperature of the GPU heatsink however.

Does this mean that the GPU diode is bad? Or did the mac os X disable the reading of the GPU diode?

If the GPU diode temperature sensor did go bad, is there any problems with running the laptop without getting it fixed?

Any help with this matter would be very much appreciated.

Macbook Pro 3, Mac OS X (10.6.1)

Posted on Sep 28, 2009 1:21 AM

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Answer 1

wlfpck Author

Level 1

5 points

Sep 28, 2009 7:52 AM in response to wlfpck

Well this is weird. I ran the hardware diagnostic test from the mac OS X cd and it said there were no problems found. Once it booted up, I can see the GPU diode temperature again.

Does anyone know what's going on?

Thanks,

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Answer 2

sig

Level 8

35,862 points

Sep 28, 2009 7:55 AM in response to wlfpck

No, but you are assuming that iStat is in fallible.

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Answer 3

wlfpck Author

Level 1

5 points

Sep 28, 2009 10:02 AM in response to sig

Well right. Now the weird thing is this. I just tried running some games and video editing stuff. The diode temper sensor would show the temperature, then it would disappear.

It's kind of weird. I'm not assuming that iStat is infallible, I'd just like to see if there is any way to determine if the GPU diode sensor has gone bad. None of my friends have a MBP with a dedicated graphics card so I can't even test out iStat on their computer.

Message was edited by: wlfpck

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Answer 4

wlfpck Author

Level 1

5 points

Sep 29, 2009 6:29 PM in response to wlfpck

Does anyone else have this problem?

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Answer 5

wlfpck Author

Level 1

5 points

Oct 12, 2009 8:39 AM in response to wlfpck

Recieved a new macbook pro.

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Answer 6

BugSquash

Level 2

285 points

Oct 12, 2009 11:33 PM in response to wlfpck

At least on mine (with the dual graphics modes), the GPU Diode only shows a reading when the graphics is set to higher performance (9600M). I assume the sensor is part of the card itself and therefore does not get a reading when that card is disabled.

If you also have a system with dual graphics modes, that's probably the cause of the issue.

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Answer 7

JCDis

Level 1

5 points

Oct 13, 2009 8:54 AM in response to wlfpck

Try to do next things.
Download the last version of iStat Menu (10.6.1 supported) http://www.islayer.com/apps/istatmenus/download/

then download Fan Control http://www.maccentre.ru/soft/data/16043/Fan%20Control%201.2.dmg

and set all this stuff up to your desire.
For example i'm using 2200 rmp of coolers instead of 2000 and my T does not go higher then 53 C (CPU) and 55 C (GPU).

Post your results.

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Answer 8

Huma

Level 1

0 points

Nov 14, 2009 3:06 AM in response to wlfpck

I have experienced the same problem just once. But I've noticed that during long (4-5 hours) session with 3D games the mbp overheat and after this the life of the battery is considerably shortened (from 9/8 hours doing basic things to 5/4 hours doing the same!). I was wondering if this two things are releted. Maybe the diode temperature sensor is broken and that allow overheating that "fry" the battery?

wlfpck the technical service told you what was exactly your problem?

Thanks and sorry for the poor english!

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Answer 9

dukeseb

Level 1

5 points

Jan 28, 2010 7:15 PM in response to wlfpck

I have the same problem on my MBP aswell..... im assuming it has to do with being on the integrated graphics rather then the performance chip..... ill update later when i test that out

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Answer 10

TarBuckI

Level 1

0 points

Feb 6, 2010 6:57 PM in response to wlfpck

When I turn on my MBP, the GPU Diode temp is around 130F and thefans run immediately and always stay on. I suspect there is an issue with my GPU Diode temp sensor. Anyone else have this problem? Is there a way to reset this? I have already done the SMC reset.

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Answer 11

May 2, 2010 9:59 PM in response to TarBuckI

I have a similar issue on my 2006 Mackbook Pro. One of my fans actually blew out a while ago because I guess it overworked. I had to replace it myself because the Apple "genius" said it was a motherboard problem and wanted to bill me for $1,200+

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Answer 12

Rod Hagen

Level 7

32,000 points

May 2, 2010 11:08 PM in response to wlfpck

On the new i5 and i7 MBPs the GPU diode won't register at all when the computer is running on integrated graphics. In such situations the discrete GeForce GT 330M processor is not receiving current and the sensor is simply sending no information. Clearly the older version of iStat is not used to this, and gives the "-128" reading accordingly.

"Hardware monitor" in such situations, simply identifies the same sensor as "disconnected". Its author, Marcel Bresink , explains this as follows at http://www.bresink.com/osx/216202/issues.html:

+In this case, you must be using a Mac capable of switching between two alternative graphics solutions, for example a pair of an Nvidia GeForce 9400M and a GeForce 9600M GT, or Intel HD Graphics paired with an Nvidia GeForce GT 330M. It is the correct and expected behavior to only show the sensors which are currently online. The sensors of the GPU which is currently offline are powered down and even cannot be detected.+

Cheers

Rod

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