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Has anyone experienced this problem? Does anyone have a solution? I have scoured the internets for solutions and found many different answers. I am on a Macbook Pro 6,1. The one that has worked for me is reset the SMC, switched to the integrated card using gfxCardStatus, not plugging in an external monitor and jacking up my fan speed to 6k RPMs. This has made my machine usable and has only shutdown 2x in the past 3 days. Anyone else have any insight? Solutions?

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Do you have examples of proposed solutions that didn't work for you? This helps prevent duplicated effort. –  bneely Feb 11 '12 at 8:26
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3 Answers

It sounds like your motherboard has suffered heat damage. The most likely culprit is doing something 3D graphics intensive, because the graphics chip can get a lot hotter than the CPU but the fan speed is controlled by the CPU temperature. Another possible cause of overheating is running Windows in BootCamp.

I've had that happen on a couple of different Macbook Pros (earlier models) and once it reaches this state you need a new motherboard. In my case, they were still under AppleCare so it was free. Since then I've always made sure to crank up the fan speeds before doing anything 3D intensive, and I installed fan controllers on the Windows side.

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Ramping up the fans to 6000 rpm in all likelihood narrows the possibility of the CPU overheating unless cooling is being obstructed (by dust and debris, which is actually a very common problem). –  cksum Mar 14 '12 at 18:10
    
This information is incorrect, the fan speed and cooling for the GPU is not controlled by the temperature of the CPU. The GPU has its own temp sensors that work with several others inside the Mac. The chances of the logic board being damaged by heat are extremely slim, especially as the components are designed to withstand heat way above the Macs operating temperature. However if the Mac does detect a state where the temperature may cause issues it may shut itself down to protect its components. –  hellothere Jul 20 '12 at 1:00
    
Not all Mac models have temperature sensors on the GPU. Many Macbook models do not have separate fans for the GPU. Even if there is a sensor and a fan, both can fail. Do some google searches and you will find many examples. Instances of GPUs and motherboards failing due to overheating are common enough that Apple has done free out-of-warranty replacements (most notably the NVIDIA issue from 2008). –  Seth Noble Jul 25 '12 at 16:52
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Test your memory modules using something like Rember or Apple's Hardware Test.

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Answers on Ask Different need to be more than just a link. It's okay to include a link, but please summarize or excerpt it in the answer. The idea is to make the answer stand alone. –  Daniel Lawson Mar 14 '12 at 14:05
    
Rember's actually quite amazing for finding certain RAM issues. AHT - not so much. It's a long stretch that it's the cause of the OP's issue, but is a fair troubleshooting step to isolate RAM from a potential cause. –  bmike Mar 14 '12 at 20:18
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Perhaps open Console, select all messages, go to the search field and type 'shutdown' (no quotes needed) and the PRAM should have logged a shutdown cause error code the next time you boot after the power off. Please post the output here. Thanks.

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