MacBook Pro slows down from pressure on the bottom (messy solution included)

macbook pro

I have some non-trivial problem. If my notebook stands on solid surface everything is fine, but if I put it on my knees (for example, it could be a book too) or just push the center of the bottom cover, the CPU usage immediately grows to 100%. It also causes issues with the WiFi.

I have MacBook Pro mid 2010, which I manually upgraded to an SSD (optibay) + 8Gb DDR. I recently disassembled it and cleaned it, but the problem came yesterday.
I tried to manually push some points on motherboard but failed to reproduce the problem, it only occurs when pushing the bottom cover.

In Activity Monitor, kernel_task is using greater than 170% CPU. There are no warnings or errors in logs during this problem.

Has anyone else seen this? What can I do (other than going to a service center)? What kind of problem could it be?

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UPDATE

I've done messy solution – place the steel coin between the bottom cap and the processor's fan. Now the bottom cap did not contact the cooler and everything's fine.

Best Answer

I would re-seat all the temperature sensor connectors.

I've read that when the machine appears hot, kernel_task slows the machine down in order to reduce the heat. The way it does this causes the CPU usage of kernel_task to appear high.

So perhaps, when you press on the cover, this distorts one of the temperature sensor cables, causing some faulty temperature readings. (I'm assuming the machine doesn't seem hot to you?)

I did a search for [kernel_task CPU heat] and found this blog post, which describes a way to "fix" this issue by modifying the kernel_task configuration so it doesn't take this action. I'd caution against this modification, though, as it doesn't fix the underlying hardware problem -- instead, it disables a (presumably important) software-based safety mechanism.

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