Mac Mini 2012, hot to the touch when doing nothing

[MR_Boogy]

I just came back to my Mac after a couple of hours and despite being sat on screensaver, the body is hot to the touch. I launched Activity Monitor to see if anything obvious was wrong, the only weird thing was Activity Monitor itself was reportedly using 20-40% CPU. The fan is not blasting, it's just sitting quiet and hot.

I'm running Catalina, it's a quad-core variant of the late 2021 unibody Mac Mini. Any ideas? I've noticed this a few times recently, but it did not use to happen as far as I can recall.

 

[r6mile]

I don't think you have anything to worry about. I have a 2012 quad Mini, and it is often warm* - the case is designed to act as a bit of a heatsink. What temps are you getting?

*Nothing compared to my work Dell XPS13 which gets very hot and loud under totally normal use...

 

[ian87w]

I have a 2012 mini, but i5 version running High Sierra. It can get hot when running things for a prolonged time (like youtube videos). But on idle, it shouldn't be. Try restarting the Mac. Also, check what apps you are running. If you have a lot of tabs on your browser, see if there's one consuming resources (ads looping/reloading infinitely, etc). I use Edge for comparison, and it behaves quite alright.

 

[MR_Boogy]

I'd definitely say hot rather than warm, is there a way to measure the temp built-in?
I would probably consider Chrome might be a culprit though I've always got loads of apps and tabs open and until recently it was always pretty cool unless the fan kicked in.

 

[ian87w]

I'd definitely say hot rather than warm, is there a way to measure the temp built-in?
I would probably consider Chrome might be a culprit though I've always got loads of apps and tabs open and until recently it was always pretty cool unless the fan kicked in.

Never liked Chrome. It's bad on Windows that I stopped using it once other Chromium based browsers are available (eg. Brave, Edge).

I use Macs Fan Control (the free version). https://crystalidea.com/macs-fan-control

 

[Fishrrman]

OP:

Lose the "Chrome".
Find something "duller", and cooler...

 

[4sallypat]

My recently sold 2012 i7 Mini Server running Catalina so hot and noisy fan spinups during the day that I had to put a netbook cooling fan underneath to increase air circulation.

Past 14 years running Intel Macs have all been warm or hot running them.
Talk about inefficiency (heat, energy consumption, lower component life)....

Glad I sold that i7 and got the M1 Mini that runs ice cold all day!

BTW got rid of the cooling fan too!

 

[MR_Boogy]

But after years without problems, why now? As simple as vents dirty?

I am curious about the M1 but not sure what Intel software I might be relying on without knowing it. Catalina already killed some of my legacy apps, although it sounds like the x64 emulation layer is actually pretty good?

 

[iluvmacs99]

But after years without problems, why now? As simple as vents dirty?

I am curious about the M1 but not sure what Intel software I might be relying on without knowing it. Catalina already killed some of my legacy apps, although it sounds like the x64 emulation layer is actually pretty good?

I suspect it's dirt and dust that's causing poor ventilation and airflow after years of not cleaning it. It's not hard to take the mini apart and clean it and re-paste the CPU. I have a 2011 Mini with the i5 that is acting as my server for all my macs and my PC and it only gets hot when it's being pushed and which is why I have an external fan sucking air out from my bottomless Mini (I took the black plastic cover out). Once I've cleaned the Mini, it works like a charm again until the next year where I take it apart again and clean it. I clean my Mac Pro and my PC the same way of dirt and dust. Otherwise, do you have the memory maxed out so it doesn't swap memory to your HD/SSD?!? Starting with Mojave, I noticed that OSX needs a lot of memory and if it doesn't have enough, it will make your machine swap memory and go crazy. The heat build up comes from my SSD as constant access can heat it up. I also find that Chrome itself, the latest version, is a memory sucker! Which is why I switched to using both Edge and Brave which don't utilize as much memory as Chrome, because that's how I kept my intel Macbook Air cool running Mojave and with only a fixed 8Gb of ram.

I would try cleaning your Mini's internal first and if that doesn't solve the problem max your Mini out to 16Gb ram. If that also doesn't help, switch Chrome to Edge or Brave which are Chrome based.

 

[Mr.Fox]

I just came back to my Mac after a couple of hours and despite being sat on screensaver, the body is hot to the touch. I launched Activity Monitor to see if anything obvious was wrong, the only weird thing was Activity Monitor itself was reportedly using 20-40% CPU. The fan is not blasting, it's just sitting quiet and hot.

I'm running Catalina, it's a quad-core variant of the late 2021 unibody Mac Mini. Any ideas? I've noticed this a few times recently, but it did not use to happen as far as I can recall.

Disassemble,clean from long-term dust, replace the thermal paste, it is advisable to use the thermal paste of the company Arctic Cooling MX-4. If it is too thick, do not be alarmed, tightly close the syringe with thermal paste and lower it for 15 minutes in warm water,comfortable for hands.
20-40% of the load - background programs work, they can warm the case.
Where do you have your computer? Place it in a well-ventilated place where there is a cold supply of air. I have often seen how many people install a computer almost in the niches of nightstands for a computer or tv-this is why the case is heated.

 

[romanof]

I am curious about the M1 but not sure what Intel software I might be relying on without knowing it. Catalina already killed some of my legacy apps, although it sounds like the x64 emulation layer is actually pretty good?

Actually, it is very good. The only app that would not run for me (so far) between Mojave and Big Sur came from the App Store, and it is still there, plus the 32bit apps that aren't going to work, anyway. I use a bunch of stuff made for Linux, and of course Apple does not make any effort to assist in that, but the programs run. And some better than in in the non-emulated iMac 27" that I discontinued. I am sure that I will hit something that bombs out, but so far their emulation has been impressive.

 

[MIKX]

This solution works for me especially in summer ( August = hottest month here )in Japan where it runs at around 40°C. Gets 1 or 2 degrees hotter under load.

Currently with winter underway ( Japan ) it is running now at 36°C. iStat Menus

Late 2012 Mac Mini Mojave 10.14.6. 16gb RAM. Internal SanDisk Ultra 3D 500gb.

( NOTE : Recently I put a fine mesh nylon dust filter over the open bottom of the Mac Mini )

I use canned air about every 2 months to remove any dust.

 

[4sallypat]

Love my M1 Mini so much, I am ordering another base M1!

No more heat issues - no more laptop cooling fan running underneath - no more thermal throttling....

Just sold my other 2012 Mini Server i7 for $500 - enough to pay for most of another M1 base:

 

[MR_Boogy]

Came to write a new thread and this one popped up from a few months back...

Last few weeks the MM has started spontaneously rebooting, the metal cover at the top was almost too hot to touch near the ports on the back when this happened. Fairly easily reproducible and sometimes it would even reboot while rebooting if I didn't give it time.

I have bodged a heat-sink on top - one benefit of a metal cover is it is a good conductor which lets me do light work but if I start watching YouTube, it will last about 5-10min. First few days I kept forgetting at lunch-time... 🙂
I have opened it up and removed some fluff and squirted air but nothing very obvious. I removed the fan to check under and it was scorching hot, with that lovely ozone smell.

I'm replacing this anyway but I'd like to have it usable. One thing I noticed is when it goes wrong, the fan is not running at the time. Sometimes the fan turns on after it reboots and you can feel it cooling down, so it seems possible the problem is because the fan isn't running when it should.

I tried to monitor the temperature but...

sudo powermetrics --samplers smc |grep -i "CPU die temperature"
unable to get smc values

Is it likely the fan may simply have failed? It would be a pain to buy a new one just to find that isn't the cause. Any way to try and find out for sure?

 

[OverTheHill]

When I first bought my Mini about 6 months ago it was doing this. And it was hot. Thought it was defective, gave it a couple of days and it stopped. Hasn’t done it since. Weird.

 

[MR_Boogy]

It was getting worse and worse and seemed the fan wasn't coming on which might've been the issue.
I installed "Macs fan control" and I can hear the fans are more active. I haven't load tested yet but it hasn't crashed since

 

[MacInTO]

Thanks, this thread is very helpful!

I got a 2012 i7 Mac mini a week ago. It was having some shutdowns due to heat. I renewed the thermal paste and the situation improved. Yes the thermal paste needed to be replaced after 14 years, regardless, the MM is very inefficient in terms of cooling. Even after new thermal paste, I saw the CPU temp go into the high 80s/low 90s when doing things like watching Youtube. The fan did not increase in speed until the CPU temp got to 90 degrees - maybe it was lower, but I did not hear it. I installed Macs fan control and had the fan increase from 55 degrees and this helps somewhat. When I removed the bottom cover, the temperature went down about five degrees in a very short period of time. The resting temperature of the CPU is about 42 degrees for me.

For a point of reference, I have a 2012 15" i7 Macbook Pro with the same processor. At rest, the CPU temp is about 36 degrees - with 14-year-old thermal paste! When it heats up, the fans kick in around 60 degrees and they ramp up to 3000 to 3500rpm. It takes almost no time for them to cool the CPU five degrees. The MBP has two fans, more vents and the bottom cover is thinner and has a larger surface area for cooling which makes it very efficient.

I think the bottom cover of the MM restricts airflow a lot. It would be nice if the bottom cover were perforated like the wifi antenna cover and it had some standoffs to provide a small gap between the desktop and the bottom cover to provide airflow. I think even if the bottom cover were made of metal it would be more efficient. It is metal on the inside, but the plastic base doesn't help matters. Without that, I think I will run this with the bottom cover removed.

 

[zarmanto]

... I got a 2012 i7 Mac mini a week ago. ... I think the bottom cover of the MM restricts airflow a lot. It would be nice if the bottom cover were perforated like the wifi antenna cover ...

I have the same Mini; I used it as a home theater PC for years. Since the advent of the AppleTV era that Mini has effectively been demoted to a Minecraft server... but it still works great, to this day.

The only time I've ever had any issues with heat was shortly after I replaced the internal HDD with an SSD. It got hot enough that it would throttle down to unwatchable framerates on movie night -- not a great look. I couldn't identify the problem for quite some time, so my workaround was a glass pitcher of ice water. I would literally put that pitcher on top of the Mini at the beginning of the movie, and all the ice within would be melted by the end. 🔥 😱 Still... that pitcher got us through several movie nights.

I did eventually pop it back open to try to figure it out... turned out that the problem was, I had accidentally disconnected the fan power cord during the drive upgrade. 🤦‍♂️ Reconnected that, and suddenly it worked perfectly again. Felt like a right fool.

So yeah... I've never bothered to touch the thermal paste nor to leave the bottom cover off, but it's always good to verify a few basic assumptions. And if all else fails... try a pitcher of ice water. At the very least, it'll help you to determine if the fan is even doing its job or not.