Mac Mini 2012 veeeeery sluggish and fan blowing full speed

[puchelaar]

Hi everyone,


I'm out of ideas, so hoping someone has a brainwave...

I have a Mac Mini 2012, i7 2.3GHz. A couple of years ago I upgraded the RAM to 16GB, and the hdd to an ssd (Samsung EVO 500GB).
A couple of weeks ago, when I thought it was sleeping, we heard the fans start up to full speed. So I went over, looked at it but did not notice anything that could cause this, and shut it down.

Last week I had some time, so started to work on it;
* started up, and even before logging in, the fan was up to full speed. After logging in, the handling was extremely sluggish. Clicking could take up to 30 seconds to register. Clearly there's a problem.
* Activity monitor shows no strange apps, BUT 'kernel task' is taking up a lot of cpu time. Apparently this points to overheating, where the 'kernel task' is making sure the cpu is not overheating. So I seem to have a heating problem.

This is what I tried:
- different account > same problem
- I had a mac mini working fan lying around, so swapped that out. No difference.
- searched the web, found that a lot of mini's develop problems because of overapplied thermal paste between the cpu/gpu and cooling block. So I got some Arctic Silver Céramique 2 thermal paste and some thermal paste cleaner. Took off the cooling block, and there was a lot of dried out thermal paste,so cleaned it all, applied new paste (very thinly) and booted up again. Still the same problem.

- installed macsfancontrol. This way I can stop the fan from going to full speed, if I take it off 'automatic', and make it react to the average cpu temp, and set treshhold for speeding up the fan to 75º (C). The Mini still feels sluggish if I do this, but less so.

So, now I'm thinking that it might be the ssd that's causing the sluggishness (though I can't quite explain the heat/fan problem).
- took a 32GB usb key, installed MacOS (used a different Mac for that), booted up from that key, and still the same problem. Seems to rule out a problem with the ssd.

So, I don't know what else to try...

Could there be a faulty sensor somewhere? And if so, can I replace it myself? I've installed ssd in a couple of Mini's, Macbooks and some iMacs (pre-tapered edge) over the years, so I'm not afraid to try out. But I'm out of ideas of what I could try.

The machine is not really usable this way, but I'd hate to part with it. It was very usable up till now.


Thanks for reading and maybe your suggestions.

 

[mikas]

You seem to have done all but reinstall the system? That's what I'd do. Kernel task should not eat cpu resources all the time when idle, but only momentarily.

About the thermal paste.
I have done a couple of Mac Mini 2012 repastes too, and I assume that the gap between the processor and GPU is determined by the attaching screws, then they reach the bottom of the thread. It's hard to measure the gap, but it seems it's not exactly leveled between the two contact surfaces either. If system/OS reinstall does not help, I'd go and check the paste once more. I would put "enough" of it, and I would use liquid enough paste so that it spreads through the contact surface evenly and every sqm of it. I don't think it's harmfull if it reaches over the edge a little bit.

I did a test fit with some paste, and reacted to that (see picture) with a little bit more paste with my actual install. It seems the gap would be a little bit higher than what I have been used to see with Mac Pro 2009-2010 CPUs. That's why a little bit more paste is needed.

Left pic, first time paste. Right pic, first time + then some additional to reach the edges of the chips too.

Mac Mini i7 is a hot machine though, no matter with what or how you paste it.
Good Luck.

 

[Aggedor]

I did a HDD > SSD swap like you did in a Mac mini 2012, and had to install a fan control app (might have been the same one as you, can't remember) as I believe the fan controller is actually part of the factory HDD setup. Without it, the fans were blowing full speed 100% of the time, straight after I installed the SSD.

 

[mikas]

Mac Mini 2010 resembles a lot a 2012 Mini, and it does have analog temp sensors and cables, but I think 2012 (and 2011 too) gets their temps from drive itself via SMART data. At least I did not need to install any fan control software after Fusion Drive demolish, and then installing two separate SSDs inside it.

 

[chrfr]

I did a HDD > SSD swap like you did in a Mac mini 2012, and had to install a fan control app (might have been the same one as you, can't remember) as I believe the fan controller is actually part of the factory HDD setup.

2011 and 2012 Minis use standard drives and don't have separate thermal sensors. The 2010 models have separate sensors which need to be accounted for.
In the case of the OP's 2012, I'd be seeing about cleaning dust from inside before going any further.

 

[Aggedor]

2011 and 2012 Minis use standard drives and don't have separate thermal sensors. The 2010 models have separate sensors which need to be accounted for.
In the case of the OP's 2012, I'd be seeing about cleaning dust from inside before going any further.

Ah, mine must have been a 2010. It's been too many years to remember clearly

 

[Honza1]

Did you reset PRAM/SMC? That would be my first step before everything else.

 

[Kaida]

If the PRAM/SMC reset fails, it's probably something on the board.

i had an 2012 like that, when you go into activity it always at cpu 100% and thermal throttling? i sent it to a shop and they did some component level repair and charged me $180... it was an i7 2.6ghz so i did the repair..

 

[satcomer]

If the PRAM/SMC reset fails, it's probably something on the board.

i had an 2012 like that, when you go into activity it always at cpu 100% and thermal throttling? i sent it to a shop and they did some component level repair and charged me $180... it was an i7 2.6ghz so i did the repair..

I’m a firm believer that on such old machine you should replaced the dried out thermal past on the processor is why the temperatures spike high!

 

[puchelaar]

Thanks for all reactions. I thought I had email notification on, but apparently not, so I'm a bit late in reacting...

Anyway, I forgot to mention that I also did try PRAM/SMC reset (twice) and dust was cleaned (compressed clean air).

Like I said, I replaced the thermal paste, but applied the new paste pretty thin. The way I always used to do when I built my own pc's a long time ago

Maybe you're right Mikas, and it's too thin. The cooling block/duct is pressed onto the the chips/motherboard it seems by the springloaded screws. However, since I can be heavy-handed, I've learned that 'tight enough is tight enough, and don't overtighten!", so me maybe I should screw them in with more pressure.

However, looking back and overthinking it all, I think I may have the same problem Kaida describes; a broken component on the logic board. After all; if I use macfanscontrol, and take it off full auto, but instead let it react to the average cpu temp (semi auto), the fan does slow down and only starts up when the temp goes over the treshhold. So the problem looks to be in the decision making software and/or the source of the temperature.

If I had a good repair shop for Macs around, I would take it in, but I think I'll keep going a bit longer with macsfancontrol and start saving up for a new Mini...

Thanks for all the input everyone. Much appreciated

 

[Kaida]

i think your problem was better than mine and sounded like a fan speed control problem only. Mine has CPU at 100% activity and thermal throttling too. So for yours, maybe its just a PWM pin not connected properly and maybe a fan replacement would have fix that if the problem is not on the board itself.