how to keep a mac mini from overheating?

Discussion in 'Mac mini' started by grcar, May 20, 2015.

  1. grcar Suspended

    grcar

    Joined:
    Sep 28, 2014
    #1
    I want some suggestions for keeping a mac mini from overheating. All macs have a basic design problem in that the external case is too small to allow proper cooling of the cpu and graphics chips. In the old days Apple put huge heat sinks on the chips which allowed them to keep cool under continual heavy use. Because the chips in the new machines are inadequately cooled, they "throttle back" when they get hot, which is a way of saying your quad-core i7 chip is not capable of running at full speed and heavy load continuously. What kind of external fans and other third-party cooling options allow a mac mini to run at 100% (400%) for a long time?
     
  2. Micky Do macrumors 68000

    Micky Do

    Joined:
    Aug 31, 2012
    Location:
    An island in the Andaman Sea.
    #2
    If you have this kind of use in mind, just get a Mac Pro rather than throw money and time at pushing a Mac Mini beyond what it was designed for.
     
  3. frank4, May 20, 2015
    Last edited: May 20, 2015

    frank4 macrumors regular

    frank4

    Joined:
    Oct 17, 2011
    #3
    I think the default fan settings on my Mini are very slow to increase the fan speed when the CPU gets hot from a big workload. The CPU temperature can get to almost 100C (the maximum temperature for my CPU) and stay there for a few minutes before finally the fan speed increases and the temperature starts to drop.

    So before I do something compute-heavy I start up Macs Fan Control which can be set to automatically raise the fan speed more quickly than the default. Macs Fan Control can be run full-time but usually I don't do anything heavy on this Mini so I just run the Apple default cooling. The only thing I don't like about Macs Fan Control is that it has quite a large number of Idle Wake Ups per second, as reported by OS X Activity Monitor, not a big deal but they should fix it.

    With Macs Fan Control running with my settings, I can run a heavy HandBrake conversion job for a half hour or so, and the temperature only rises to about 80C.

    http://www.crystalidea.com/macs-fan-control

    I have done a small amount of testing and concluded there is very little additional cooling obtained by running fans under the Mini, or removing the bottom cover. I just run it on a clean desktop with nothing on top.
     
  4. grcar, May 20, 2015
    Last edited: May 20, 2015

    grcar thread starter Suspended

    grcar

    Joined:
    Sep 28, 2014
    #4
    reply

    Dear Micky Do, So you advise buying a mac pro. Minimum $2999 for a quad core. Oh, wait! Ebay has quad core mac minis for about $1000. Do the math. And you think the mac pro will not overheat?

    Dear Frank4, Thanks for the advice.
     
  5. Gav2k macrumors G3

    Gav2k

    Joined:
    Jul 24, 2009
    #5
    I can pin both my mini's i5 and i7 at 100% without 'throttling' they just sound like they are going to take off in the process lol
     
  6. yjchua95 macrumors 604

    Joined:
    Apr 23, 2011
    Location:
    GVA, KUL, MEL (current), ZQN
    #6
    It will take a massive job for a Mac Pro to overheat. I've done massive 4K video editing (footage from an Arri 4K camera), and the Mac Pro's fans barely make a whisper. This is because of the thermal design. A Mac Mini doing the same job will have its fans go noisy within half a minute, but a Mac Pro (especially the cylindrical one) would take over an hour or more before the fans go noisy.

    You pay what you get for. Keep in mind that the nMP has way better hardware than the Mini in every way (Xeon CPUs, ECC RAM - these are pricey, PCIe SSDs as standard - these custom-built SSDs don't come cheap either, and custom dual AMD FirePro GPUs - these are pretty cheap if you compare them to the market value. Apple somehow managed to get a great deal on these GPUs from AMD to be used in the nMP).

    A Mac Mini isn't designed for heavy, sustained work. It is only intended to be used as an entry-level Mac or a HTPC, or some tasks like light-medium 1080p editing.

    But if you want, just go ahead and let the Mac Mini heat up as it is, because the fans will spin up to the max to cool it down. If it truly overheats, the Mac will automatically shut down. Some people have been doing this for years on MBPs and they're still running strong.
     
  7. Axeros macrumors member

    Joined:
    Mar 11, 2014
    #7
    I'd differentiate between additional active and passive cooling. I haven't tried any additional active cooling myself, but w.r.t passive cooling I bolted my quad i7 Mac Mini with a metal bracket to a stone wall in the room it's in. The wall is cool even in summer, and the metal bracket helps transfer some heat. Whether it's effective for you will depend on your work load and ambient environment.

    W.r.t active cooling there are various server racks on the market which are designed to house Mac Minis. You could take a look at their designs and the placement of their fans & vents for cooling.

    e.g. ranging from (which looks it probably only uses fans for the power supply)

    xMac mini Server

    to
    NA381TB

    and at the extreme:-
    The 160 Mac mini server rack

    ----------

    This is really over simplistic. For dual core i5 models you might have a point, but it depends very much on the model: the quad core Mac Minis have benchmarks that put them well above such "entry-level" tasks.
     
  8. yjchua95 macrumors 604

    Joined:
    Apr 23, 2011
    Location:
    GVA, KUL, MEL (current), ZQN
    #8
    Benchmarks are artificial. Try rendering a heavy 1080p scene without a dGPU.
     
  9. Axeros macrumors member

    Joined:
    Mar 11, 2014
    #9
    Once again over simplistic. Benchmarks provide a useful means for comparison. Artificial? Only in the sense that to provide a common standard of comparison, they aren't the exact task you personally might be running. If anything is artificial, it's your example of 1080p rendering - it's just one possible computing task out of thousands.
     
  10. grcar thread starter Suspended

    grcar

    Joined:
    Sep 28, 2014
    #10
    Because this thread is still getting comments, I should mention several web pages advocate remounting the heat sink using a higher quality of thermal paste (search "mac mini thermal paste" on google). They generally report new paste reduces the cpu temperature about 8 degrees in all loads. This fix seems to be particularly important with the mid 2011 macmini5,2 which was the last to have a separate GPU chip. The heat sink in the mac mini is a complicated L-shaped metal part that covers the CPU (and GPU) with one one arm and has several air ducts on the other arm to channel air pushed by the fan just before it exits the unit at the long slit at the back. By the way, if I were going to change the thermal paste, I would have it done at a good repair shop rather than do it myself.
     
  11. oneMadRssn macrumors 68040

    oneMadRssn

    Joined:
    Sep 8, 2011
    Location:
    Boston, MA
    #11
    Agreed, though on my 2012 QC the temperature only dropped a few degrees as idle. However, without any actual data to back this up, I think the temperature transfer is more efficient at high-load levels and thus it cools quicker.

    I read that Tuniq TX-4 is the best paste for the Mac Mini (and most other Macs) because it's thicker than Arctic Silver, and thus better for applications with a wider gap between the CPU and heatsink, and where the heatsink might not be perfectly smooth - both true of the Mac Mini.
     
  12. ActionableMango macrumors 604

    ActionableMango

    Joined:
    Sep 21, 2010
    #12
    The classic Mac Pro has overengineered cooling. There are people who have upgraded their Mac Pros with dual CPUs that exceed the maximum TDP of CPUs offered by Apple, and even those don't overheat when used with maximum loads for sustained jobs.

    If you mean the new Mac Pro, the entire machine was engineered for thermal design and heavy loads from the beginning. Nobody has complained about heat throttling in the MP forum. If anything, they marvel at how cool it runs at maximum load.

    But back to the topic at hand, yes you are right, the Mac Mini has heat issues during sustained jobs. I used to do video conversion on a MM before I could afford a MP, and that sucker got extremely hot and extremely loud, quickly. I found that pre-emptively setting the fan's minimum speed about 50% higher held off the hot/loud state quite a bit. I think the fan profiles for the Mac Mini are probably perfect for casual computing, but too conservative for a heavy user. To be fair though, the MM isn't really meant for that sort of work. When I switched from the MM to the MP, Automator jobs that previously had to be run overnight could be done in less than 2 hours on the MP.

    Today my MM runs inside a cabinet safe with no airflow, but it doesn't get hot at all because it's just doing file server duties these days.
     
  13. mmomega macrumors demi-god

    mmomega

    Joined:
    Dec 30, 2009
    Location:
    DFW, TX
    #13
    I haven't found a need to make a change, my 2012 QuadCore has been running 24/7 and will run at 100/400% many times /week crunching video files for near 3 years. It has been on battery backup so I can't recall it ever being shut down, just restarted with system updates.
    It just sits on a shelf and does it's job. I can forget it's there because I only have it set to start video work while I am at work or during the night.
     
  14. ChinkyBob macrumors regular

    ChinkyBob

    Joined:
    Oct 10, 2014
    #14
    Well mine was starting to get a little hot occasionally, usually only during Handbrake AVI to MP4 batch conversions.
    So I upgraded the Ram from 4 to 16GB and HD to a 1tb SSD, and blew out what little dust there was in the process from the fan.
    This alone has made an unexpected difference and I barely hear a peep.
    Maybe my 5400rpm Harddsik was heating up a lot more than I thought.
    FWIW I have a late 2012 i7 QuadCore 2.3 Mini.
     
  15. grcar thread starter Suspended

    grcar

    Joined:
    Sep 28, 2014
    #15
    There is a very interesting post by rwprater in the thread called "2012 i7, overheating, three tones, need opinions". He found, with the thermal paste removed from the heat sink, the sink was not making contact with the graphics chip and was only partly touching the cpu chip. The sink has a complicated design that flexes and warps a bit when mounted. He replaced one of the spring-loaded screws and got contact everywhere. Temperatures under heavy load dropped from over 100C to 74C. Check it out if you are able to do it yourself.
     
  16. rwprater macrumors newbie

    Joined:
    Jul 14, 2015
    Location:
    MidWest
    #16
    ==========
    RePost
    ==========

    Apparently a lot of people have this problem with the i7 2012. When running Handbreak to convert a movie my Mini would run at %100 CPU for over an hour at 102C degrees. Sometimes peaking at 105C. In addition, the temps of the 4 cores should have been close to one another but core-1 was consistently 7 degrees higher than the others. I tried a lot of things including taking the bottom cover off and blowing a fan toward at it but that didn't help. With core-1 being so high I wondered if the heatsink was making good contact.

    I took the Mini apart, removed the heatsink, and cleaned the heatsink compound off. Afterward I put the heatsink back on with the spring-loaded screws exactly as it was WITHOUT heatsink compound - then I held up the board edgewise to the light and found that there was a partial gap between the heatsink and CPU (I could see light between them). The heatsink on the graphics chip wasn't touching the chip at all. I could press down on the heatsink near the middle and make it contact both chips. Apparently the spring loaded screws were just not strong enough to press the heatsink down on to the CPU and graphics chip. In addition, the screws have a shoulder that will not permit you to tighten them down more.

    I experimented with other screws for the heatsink. I had an assortment pack of laptop screws that I used in place of the spring loaded screws. I snugged them until the heatsink contacted the CPU & graphics chip (I did not over-tighten). I found that I could still use all the spring loaded screws except in one position. I left a laptop screw in the screw position near the outside of the dog leg of the heatsink where the plastic cowling hooks in. I took the heatsink off again and re-applied heatsink compound and reassembled using the one laptop screw in the position mentioned. Because of this I didn't install the plastic cowling that fits over top of the heat pipes. Kinda looked unnecessary anyway.

    After reassembling and testing again with Handbreak I found my CPU temps were down about 24C degrees. When I take my bottom cover off during the handbreak test the temps drop to 74C degrees (no outside fan). In addition, the temps for the 4 cores vary a bit as you would expect but are within a couple degrees of the other cores. This tells me that the heatsink is now making better contact with the CPU.

    That was my experience. Hope it helps.
    Randy
     
  17. rwprater macrumors newbie

    Joined:
    Jul 14, 2015
    Location:
    MidWest
    #17
    =====

    Sometimes if I have some video conversion to run, and I can let it run at night while I'm asleep, I use an app called "App Police" that allows you to assign max CPU to use for a given running app. You can throttle it down so it runs cooler. Works good and is free. I also use it if I'm working and don't want the video processing to slow me down. You might find it useful also. http://definemac.com

    Randy
     
  18. Andy2k, Jul 18, 2015
    Last edited: Jul 18, 2015

    Andy2k macrumors member

    Joined:
    Jul 18, 2015
    #18
    I would recommend replacing Apple's cheap TIM with a new performance TIM of your choosing. I have changed the thermal compound on all of my Mac's and don't regret doing it on any of them. I had an immediate drop of 20 C on my (Late 2014) Mac Mini after replacing the TIM. YES late 2014 and the paste was already clumping and dry as a bone. In the manufacturing process, Apple uses too much TIM and too low of quality, as in, it doesn't last a year without drying out. I am posting pictures of my (late 2013) rMBP. As you can see in the pictures they paste is clumpy, dried out and pretty much worthless. Replacing the TIM on a rMBP is cake, as long as you have the correct Pentalobe screw driver. You remove the cover and the heat-sink is right there, no further disassembly required. It's so much nicer to use now that the palm rest doesn't get so hot and make my hands clammy. It also runs about 6 degrees Celsius cooler (at idle or low load) at 200 RPM lower than before. It actually seems like I get about an extra half an hour out of my Macbook. Lower fan speed = lower overall power consumption. All of my Mac's are now happy and cool as a cucumber. Any one else replace TIM what's your experience with it?
     

    Attached Files:

  19. Synchro3, Jul 19, 2015
    Last edited: Jul 19, 2015

    Synchro3 macrumors 65816

    Synchro3

    Joined:
    Jan 12, 2014
    #19
    My Mac Mini i7 quad 2.3 GHz gets hot when under load. But fan speed seems to remain at 1800 rpm. Increasing the fan speed manually to 4500 rpm helps. 4500 rpm is not too loud, it's more like a rustle:

    Mac Mini - under load.png Mac Mini - under load with fan.png


    Maybe I should remount the heat sink and use a higher quality of thermal paste...
     
  20. Celerondon macrumors 6502a

    Celerondon

    Joined:
    Oct 17, 2013
    Location:
    Southern Cal
    #20

    Perhaps you should remount the heat sink with higher quality thermal paste but I have a question that you should probably answer first.
    How can any 2012 mini reach >90° C without the fan leaving the 1800 RPM idle speed? What you have proved with your fan experiment is that some parts of the cooling system work. The fan speed on your Mac should begin rising when the CPU temps climb above 85° C. If the fan control system worked properly you might not have any problem at all. Thermal paste is critical to component cooling but it has nothing to do with the fan control system.
     
  21. Synchro3, Jul 19, 2015
    Last edited: Jul 19, 2015

    Synchro3 macrumors 65816

    Synchro3

    Joined:
    Jan 12, 2014
    #21
    Are you sure the fan should begin rising above 85C?

    I guess the sensor that controls the fan is getting warm later than the CPU (for this test I was running GeekBench three times to get 94°C, maybe not enough to increase the fan rpm).

    Frank also wrote his Mac Mini is getting almost 100°C for a few minutes:
    @ frank4: How many rpm do you set under load?
     
  22. Andy2k macrumors member

    Joined:
    Jul 18, 2015
    #22
    How long does geekbench run during its test? Or is it continuous? I use Prime95 (free but not in the App Store) for stress testing with the maximum settings. The fan should increase RPMs if you try that. Keep an eye on it though, running it in maximum heat mode really taxes the CPU. Make sure your temps don't go through the roof. Your temps don't look terrible either. Especially for a Sandy Bridge i7 but your Mac should increase fan speed on its own. My Mac Mini i5 Haswell goes up to about 4000 RPM after 10 - 15 minutes of Prime95 but it levels off there. Max RPM is 4800. So it can keep it sufficiently (90 - 91 C on both cores) cool at absolute full load about 800 RPM under max fan speed.
     
  23. Synchro3, Jul 19, 2015
    Last edited: Jul 19, 2015

    Synchro3 macrumors 65816

    Synchro3

    Joined:
    Jan 12, 2014
    #23
    Geekbench is not continous, just started it again when it finished. Therefore the gaps from 3.1 GHz to 1.1 GHz CPU speed in my pics above. Under load it's always 3.1 GHz. When idle 1.1 GHz. In fact, I wonder why this Mac Mini is referred as a 2.3 GHz machine.:)

    Prime95 did not work, it suddenly crashed after start. I will test the Mac Mini with Handbrake and HD footage next week. Wondering if it will increase fan speed on its own.

    Thanks for your replies!

    Edit: Max temperature for the Mac Mini Core i7-3615QM is 105°C: http://ark.intel.com/de/products/64900/Intel-Core-i7-3615QM-Processor-6M-Cache-up-to-3_30-GHz

    In comparison with my Mac Pro Xeon W3690 which is around 90°C.

    By the way: The Intel Power Gadget is a free diagnosis tool: https://software.intel.com/en-us/articles/intel-power-gadget-20
     
  24. grcar thread starter Suspended

    grcar

    Joined:
    Sep 28, 2014
    #24
    This thread is the only place I've seen these issues discussed. From frank4 we've learned that the software control of the fan is too conservative or maybe faulty. From rwprater we've learned that a properly installed heat sink can make faulty contact with the chips it is supposed to cool. From Andy2k we've seen the thermal paste applied by Apple is defective.

    As the proud owner of a mac mini paperweight, I'd like to see Apple issue a recall of the machines to fix the thermal problem.
     
  25. Andy2k macrumors member

    Joined:
    Jul 18, 2015
    #25
    I agree the Apple fan control settings are way to conservative. I don't see much increase in fan RPMs until, at least, 1 of the cores reach 90 C or greater. I like a quiet computer but not at such high temps. Plus, I can hardly even notice any fan noise until it goes above 3200 RPM. Just to clarify the pics are from my 2013 Retina MBP. Believe it or not my late 2014 Mac Mini paste was the worst. I was astounded that the paste was clumpy and mostly dried out before it was even a year old. Just take your time and follow the instructions on how to disassemble. I usually watch an online video too before I attempt it. Just to see if I feel comfortable taking it apart and the steps needed to do so. Keep us posted if you decide to replace the TIM.
     

Share This Page