Mac mini M4 warm during sleep, cool when awake

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Level 2

183 points

Mac mini M4 warm during sleep, cool when awake

Does anyone else see this?

My new M4 Mac mini is cool to the touch when in use, yet when it's asleep it's warm to the touch most of the time. I assume this is background tasks, but it does seem odd the fan is not controlling the temperature during sleep, I wonder if the fan is actually off during sleep - but it's silent in typical use, so I cannot tell.

As soon as I wake the machine, the temperature falls to be cool to touch in a few minutes, which supports the fan is likely off during sleep. I am of course worried about the long term unnecessary stress on components by running them hot. Normally I turn my computers off, the only reason this is left on is due to the power button placement, but it's not a major hassle to lift to use, if that is the fix.

I suspect it's iCloud that's running in the background, last night Activity Monitor has logged 465GB data written and 281GB read, I rebooted not long before sleeping - so much of this was durning sleep. This sounds like a lot of data to read/write, even if awake. But it could be initial syncing and indexing, but still a lot! If this was all the time, I can't see the SSD lasting long.

Does anyone else see this? It's by chance I noticed the heat, because typically you don't touch your computer do you?

I do have a support case with Apple, hardware test passed, plus I've tried the following: -

Sleep from new blank standard user - does not get warm.
Sleep from login screen - does not get warm.
Sleep from duplicate main admin account logged into iCloud - gets warm during sleep
Sleep with "wake for network access" disabled - did not get warm in 4 hours (short test)

All this indicates it's a software "issue", if it's an issue, the GB of data written could likely be more of an issue, even if the temp isn't.

Anyone got any ideas?

Mac mini, macOS 15.1

Posted on Nov 23, 2024 7:52 AM

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Answer 1

Top-ranking reply

den.thed

Level 10

82,570 points

Nov 23, 2024 8:12 AM in response to Neil Curry

Test #5

Turn On "Prevent automatic sleeping when display is off"

Set "Turn display off when inactive" to 5 or 10 minutes

Leave the Mac mini On and only allow the display to turn Off.

Then Shutdown for longer periods of non-use if desired.

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Answer 2

Neil Curry Author

Level 2

183 points

Nov 24, 2024 3:06 AM in response to seaandnature

@seaandnature I 100% agree that sleep should be sleep, but by default unless you disable wake on LAN, iCloud sync and updates download in the background. Although there seems to be processing going to too, which causes the case temperature to rise, although it could be the SSD contributing to this too from the large disk writes during the night. Last night with the display off at the Lock Screen the temperate ranged 21-25 degrees on top of the case (room temp sensor logging), with a 4 hour period of 25 degrees, but the temp wasn't spiking to over 30 degrees as it was in sleep, over 30 is warm to the touch, whereas 25 is not really.

I think the issue here is, however little power the Mac is using when sleeping, and due to the heat I suspect that's often more than the stated figure, it's still not zero, as I would be when powered off. For all of Apple's green credentials, creating a computer where the power button is on the bottom encourages people to leave it on - it certainly did with me, now I regret it.

As for the sleep 'bug' being fixed, I would not hold my breath, I have bugs I logged years ago for MacOS and iOS that have not be fixed, they are reproducible and on multiple devices... So this 'bug' isn't being fixed, I suspect many don't notice if they don't touch the case. I will be powering off in future.

On a side note this M4 Mac mini is blazingly fast!

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Answer 3

Neil Curry Author

Level 2

183 points

Nov 23, 2024 8:31 AM in response to hcsitas

Thank you both, I will try disabling sleep and just locking to see what that does overnight. As it's not asleep, the fan should run as normal and keep the system cool, of course if this works it would indicate there is an issue with fan control during sleep, or lack of. I will of course feedback to Apple, but I suspect this won't go anywhere.

The other issue was the large disk usage whilst asleep (Activity Monitor), but that could be a new Mac thing. Last night it wrote almost as much as the size of the SSD (512GB). Although I'm skeptical of how APFS shows usage as the file size of my photos library is showing as 120GB in one place, and 12GB in another - I assume the larger as the full iCloud size, the smaller is the local synced size.

Above is around 16 hours since boot, sleeping most of the time.

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Answer 4

hcsitas

Level 6

12,902 points

Nov 23, 2024 8:20 AM in response to Neil Curry

+1 @den.thed, adding: Sleep is unnecessary on later Macs and should be disabled. Shut for long absences/idle overnights i.e and for regular operation, use the settings exactly as shown by @den.thed

Also, do not manual-sleep for brief absences, use instead the Lock Screen settings to switch the display off on timer.

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Answer 5

den.thed

Level 10

82,570 points

Nov 23, 2024 8:55 AM in response to Neil Curry

You're welcome.

That disk usage has accumulated since the last restart.

It could be from iCloud, Time Machine backup or any number of third party App's that scan or sync.

Download and run the free version of EtreCheckPro, from > https://etrecheck.com/en/index.html

Then post your Report, as per > How to use the Add Text Feature When Post… - Apple Community

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Answer 6

hcsitas

Level 6

12,902 points

Nov 23, 2024 8:47 AM in response to Neil Curry

Any and all issues related to Sleep boil down to faulty operation because it’s totally unnecessary these days. Reporting such to Apple is a complete waste of time.

Disable Sleep using @den’s settings and keep it disabled permanently irrespective of whether issues get resolved. If problems persist or new ones crop up, start a fresh discussion so troubleshooting can be more focused.

All the best.

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Answer 7

Nov 23, 2024 4:53 PM in response to Neil Curry

I am a bit puzzled by the definition of sleep here. I have an M1 Mini, and for me, when the computer is in sleep mode, it should do nothing apart from wait for a signal from a connected USB keyboard or mouse and, if enabled, listen on the LAN port for a wake-on-lan.

Anything else I would not define as sleep, but rather as doze lightly. I would not want the fan to run in sleep mode, because it simply should not be necessary. I would most certainly not want any online iCloud activity in sleep mode.

If my Xbox updates and downloads apps when switched 'off', it is because I have enabled this feature and the machine is not really off.

Suggesting to disable sleep mode all the way misses the point for me, especially with everybody going on about how little the machine specifically uses in sleep mode. Sure, then it will stay cool all along, simply because the fan is constantly running to cool a machine that is constantly using energy.

By the way, reading of these huge data amounts being written, once again, I cannot imagine how this does not impact longevity of the SSD.

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Answer 8

Nov 24, 2024 6:03 AM in response to Neil Curry

This detailed article explains that sleep basically does not mean sleep most of the time:

https://www.intego.com/mac-security-blog/what-does-your-mac-do-when-its-sleeping

Sounds great for three letter agencies around the world.

And, yes, regarding bugs not being fixed, Spotlight on my Sonoma installation would write dozens of GB a day to the SSD if I had not totally disabled it via SIP and terminal.

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