MacBook Pro Overheating easily, but not with battery removed

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Level 1

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MacBook Pro Overheating easily, but not with battery removed

Hello,

My Macbook Pro consistently overheats to the point of sudden shutdown while doing any relatively intense applications (like rendering a video file). I have been monitoring the temperature via SMCFanControl, and the temperature will get over 130 F. However, if remove the battery while the temperature is that high, the temperature will almost INSTANTLY drop to under 90 F, and never get too hot again, even while rendering.
Has anyone else experienced this drastic of a difference in reported temperature, or know how to fix this?

Thanks.

Macbook Pro 15" 2 GHz Core Duo, Mac OS X (10.5.6)

Posted on Feb 21, 2009 11:57 AM

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Answer 1

Allan Jones

Level 9

79,598 points

Feb 21, 2009 12:13 PM in response to TraciiRoxx

130F is a very happy temp for normal use. Graphics-intensive processes can run temps to the 150-180F range but that's still within the tolerance level.

The reason it runs cooler with the battery removed is that the MBP clocks back its processor when no battery is present. See this Apple article for more details:

http://support.apple.com/kb/HT2332

Although the article does not specify the clock-back amount, some say it's half the processor's full speed and others say it goes to 1Ghz.

If you are seeing 130C--not F--then something is not right and the shutdowns are expected. The system should do a safety shutdown somewhere in the vicinity of 100C or 212F -- varies a little depending on the MPB version.

You should run Activity Monitor to see if there are any runaway processes showing when the computer is idle. That can run the temps up. If you have not run Activity Monitor, you will need to change the "Show" pulldown at the upper right from "User Processes" to "All Processes."

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Answer 2

TraciiRoxx Author

Level 1

0 points

Feb 21, 2009 12:36 PM in response to Allan Jones

My mistake. All my temperature values were in Degreec C, not F. There don't seem to be any runaway processes when the computer is idle. I only see the temperature spike when I am doing something taxing to the CPU.
I routinely hit close to 100 C, and often exceed that until protective shutdown.

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Answer 3

S.U.

Level 6

9,601 points

Feb 21, 2009 3:04 PM in response to TraciiRoxx

Welcome to Apple Discussions!

You might also want to try running the extended version of the Apple Hardware Test, just to check that the fans and thermal sensors are functioning properly.

What happens if you do not use SMC Fan Control?

You can also use iStatPro to monitor temperatures and fan speeds.

Good luck!

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Answer 4

TraciiRoxx Author

Level 1

0 points

Mar 24, 2009 6:45 PM in response to S.U.

I have run extended hardware tests and nothing seems to show up as abnormal. I tried a few things; I did a fresh install of OSX Tiger (I have been running Leopard for some time). I strained the CPU for quite some time at 100% per core, and the temps pretty much stayed maxed at around 99 Deg C. I then did a fresh install of Leopard, and did the same tests. The system did a thermal shutdown in less then a minute. Any ideas on what could be going on?

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Answer 5

S.U.

Level 6

9,601 points

Mar 24, 2009 7:33 PM in response to TraciiRoxx

Something still seems very wrong. I'm wondering if the heat sinks are non functional or something like that? Maybe the thermal paste or pads need to be replaced. Or maybe there is some blockage somewhere so that the fans are not able to move the air through the Mac to cool it properly. It may be necessary for some one with a trained eye to open it up and take a look. Do you have access to an Apple Store? If so, it may be worth seeing if a genius has some idea of what is wrong. I believe that they have more sophisticated hardware tests that could be run. If no Apple Store, maybe an AASP. This sounds like a hardware problem of some sort, but maybe not one that is specifically tested by the AHT.

Good luck!

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Answer 6

TraciiRoxx Author

Level 1

0 points

Apr 8, 2009 7:47 PM in response to S.U.

I have not had a chance to get to an Apple store yet. I have some doubts as to any additional info that they would be able to provide. However I was looking at some iStat temp values and noticed something odd. My CPU A is at 73 Deg C, and my Heatsink A is only 36 Deg C, Heatsink B is 38 Deg C, and the Enclosure Bottom is 39 Deg C. Does this seem right? Could this help identify the problem?

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Answer 7

S.U.

Level 6

9,601 points

Apr 8, 2009 8:00 PM in response to TraciiRoxx

Your CPU A sounds high. For comparison, my CPU A is 51℃, Heatsink A is 51℃, Heatsink B is 39℃, and the enclosure bottom is 28℃.

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