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Comment by mintplant | Hacker News Reader

My new ThinkPad, which I absolutely love otherwise, keeps the CPU fans running if I put it to "sleep". Which left me completely flabbergasted the first time it happened! I've had to force-enable hibernation and use that for any kind of backpack travel. Which will shorten the lifespan of the SSD, but what else am I supposed to do?

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Is it running Windows? I've found that on Linux this specific issue doesn't happen, it will turn off the fans, and they will stay off. But the battery is still drained, even though, on average, I tend to get better battery life than with Windows on the same machine.

But Windows tends to wake it up randomly and do God knows what, since the PC will actually be hot to the touch.

Bonus points for attempting to install updates, then reboot, only to end up stuck waiting for the BitLocker PIN.

The BitLocker thing is definitely a problem. On Apple systems which have a similar FDE system, the preboot environment will shut the machine down if the page is left open for too long. The CPU/GPU (if present) are in a pre-power-management state during this time too, so the laptop will really heat up.

I wonder how limited the preboot BitLocker screen environment really is. Could there could be some flag set by the UEFI that says "I'm a laptop and the lid is closed without power connected, shut down after a timeout".

In my case, my computers will end up on that screen in two cases.

The first is my desktop, without a TPM, which will ask for a BitLocker password. In this case, if I'm not fast enough, it will shut down the computer.

The second is my work laptop, which I usually expect to reboot or otherwise am around when it ends up there, in which case I'll usually type in the PIN quickly enough. However, I expect it to have a similar behavior as the first case, although I haven't tried.

But the reason I know this happens, is that I once left this PC attached to my 32" screen next to my bed, and it woke me up at night. I just went and forcibly shut off the thing.

So apparently this is actually configurable, but it's either on or off, and it's set to one minute by default (either 1 minute or no shutdown, no inbetween).

The command in question is ```bcdedit /set {bootmgr} bootshutdowndisabled 1```.

https://www.tenforums.com/antivirus-firewalls-system-securit...

>But Windows tends to wake it up randomly and do God knows what, since the PC will actually be hot to the touch.

For the best part of a decade the first thing I do on any mobile device I touch is disable wake calls in the power plan settings. Learned it the hard way after the T420 woke me up multiple times per night with loud beeps...

I think Windows will shorten the lifespan of your SSD even if you use "shut down", at least if you don't disable "fast startup". "Fast startup" basically replaces "shut down" with a light form of hiberation, which makes shutting the machine down take a long while and turning it on about a second faster. Not worth the tradeoff in my opinion. I also got some bugs when using fast startup, sometimes the sound wouldn't work until a reboot or my WiFi took weirdly long to connect. This is on a Lenovo Yoga/IdeaPad.

> Which will shorten the lifespan of the SSD

Technically true, but not enough for you to notice.

Modern SSDs have drive write lifetimes in the high hundreds of TB of writes.

If you had 128GB of memory in your laptop, writing that down to disk isn't going to consume much of that write lifetime.

On the contrary, you're telling me that shutting the laptop lid three times a day for a year will wear out the SSD by 20% of its lifespan.

What you say and the math does not agree. Do it 10x and in your scenario already 1TB is consumed of those "hundreds of TB of writes".

Most laptops don't have 128GB RAM, they're probably 16GB or 32GB.

Samsung warranties their 990 Pro SSD at 600TBW for 1TB, 1200TBW on 2TB, and 2400TBW on 4TB.

So, lets assume you've got a laptop with 32GB RAM and a 1TB SSD. If you hibernate it 3x per day. After 10 years you'll have used 350TB of your writes.

(32GB * 3) * 365.25d * 10y = 350.64TB

Unfortunately a lot of Laptop manufacturers were forced to leave the fans on all the time due to overheating which would cause battery issues if they didn't run the fans.

I remember getting a BIOS update on my Dell a few years ago that permanently turned the fan on too.

There shouldn't be any overheating when in S3, from what power usage ??

And they can wait to switch to S3 (and shut down the fans) once the temperature got low enough, a bit like how with S3+swap, the computer won't enter suspend until the RAM has been copied to swap.

You can reenable S3 support on many thinkpads, it's in the bios they call it "Linux sleep".

Unfortunately not on mine, it's unsupported at the hardware level :/ This is the norm for newer laptops sadly.

If your notebook has 16 GB of RAM that needs to be written out every time it hibernates, and you do that three times a day, five days a week, you’d accumulate about 63 TB of writes over five years. That’s roughly a third of the TBW rating for an average 256 GB SSD. A typical 1 TB SSD would have three times the endurance or more.

I think your SSD will handle it just fine. :)

I'd say 1/3rd is a rather large chunk of an SSDs TBW if its just for hibernating. In practice, for reasons you outlined, it would be a smaller amount but I would only find 1-2% tolerable.

Chances are, the computer will break or be replaced in five years or less. It doesn’t really matter if you reach 2%, 33%, or even 90% of the TBW if the system or component is replaced before it uses up all its writes.

> Chances are, the computer will break or be replaced in five years or less.

I think this is less and less true as time goes on. I have a laptop from 5 ish years ago I still use and it's actually pretty fast.

And, even so, it's not like the ONLY wear on your SSD is the hibernation. So this 5 year figure, I'm not sure it's right. I think, maybe if you're someone who stresses your hard drives a lot (maybe you work with photography or videography?) hibernation might make an impactful difference.

The five-year estimate is based solely on hibernation writes, which is a very conservative figure. In reality, most users will use closer to 2% of the TBW for hibernation, not 33%.

For those with heavy I/O workloads, they likely have higher-grade or larger SSDs with a higher TBW rating.

Additionally, TBW isn’t a hard limit and can often be exceeded, with some drives lasting beyond 200%.

For most users, TBW won’t be an issue, and other components are more likely to fail before the drive wears out.

My previous ThinkPad lasted eight years before I replaced it with this one.

I've got 128 GB of RAM, heh.

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