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Comment by Raed667 | Hacker News Reader

> laptop overheating if being put in the backpack

I killed a macbook air exactly like this. It just decided not to shutdown like usual.

Usually I'd put it on sleep mode, or just close the lid and it is fine, but it only took one time for it not to work properly to find the insides of my backpack like a sauna.

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Is there even a way to make sure a MacBook is actually turt really off?

sudo pmset -a hibernatemode 25

The dumb thing is you can't choose to do sleep vs hibernate; you have a system global setting which decides what "sleep" means. (AFAIU You need to have two shell scripts sleep.sh and hibernate.sh to change the hibernate mode if you want to be in control on what's gonna happen)

> It just decided not to shutdown like usual.

This happened once or twice with Windows laptops for me (Lenovo and Asus); but each time the laptop survived. Was yours a fanless model?

It was probably the 2017 model, it had a fan. But it was in the tight pouch within the backpack that was supposed to protect laptops from bumps, so it didn't have much room to breath.

Same thing happened to me with my Surface Book. I found it the next day with fans at max and burning hot. Still survived. Why aren't laptops shutting down when the CPU gets unbearably hot?

"Unbearably hot" for meatbags and "unbearably hot" for CPUs are different things; meatbags start having troubles at 50°C, while internal components are fine until 90-120°C.

Traditional hard disks are the biggest exception, but I'm fairly certain that's not a worry for a Surface.

Good question, they do turn off the discrete GPU when it gets too hot.

How can a fan help when fresh air is nowhere for it to suck from? I even suspect fan-less models may be better prepared for such scenario.

Even when there's not much fresh air supply, it can circulate the existing air over a larger volume and transfer heat faster into whatever material surrounds it. Doesn't help much, but might be the difference between "it's burning my fingers but still works" and "it died".

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