Retina 2012 13" MBP overheating (>100ºC)

Discussion in 'MacBook Pro' started by imrazor, Mar 15, 2018.

  1. imrazor macrumors regular

    imrazor

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    #1
    I recently picked up a 2012 Retina MBP 13" with a broken screen that I've been using as a desktop until I can get the screen repaired (or do it myself.) I've noticed that when doing something as innocuous as playing HD video the temperatures can get quite high.

    Picture1.jpg

    Now that is with 12 or so Firefox tabs open, and Mail, Word, iTunes and few other programs idling in the background. Despite that CPU usage doesn't seem to be going over 60%. Things are a little better if I close everything except Safari, but temps still hit 93ºC when *just* playing Youtube video.

    Is this normal? I've heard that MacBooks run hot, but that seems a bit much.

    Does it need to be blown out with a can of air? Do I have to remove the bottom (with its lovely pentalobe screws) to accomplish this?
     
  2. impulse462 macrumors 68000

    impulse462

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    #2
    Not normal temps with your usage. You may have to re apply thermal paste and definitely clean out the fans and vents with compressed air.
     
  3. maflynn Moderator

    maflynn

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    #3
    Open it up, being so old, the fan may have dust that is inhibiting its function, otherwise as noted above, it may not be a bad idea to reapply the thermal paste.
     
  4. leman macrumors G3

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    #4
    100 C is the maximal safe operating temperature for Intel CPUs. I suppose that the video you are playing is not using any dedicated decoding hardware, instead relying on general-purpose CPU execution units. Under these circumstances, its not unusual that the CPU's ALU utilisation is close to 100% (since it is basically running a lot of intense math) and so high temperature is not unexpected. Of course, this is not really sustainable in long term, since your battery will go down very quickly. This is why contemporary CPUs/GPUs have specialised decoder units which can decode mainstream video formats while using very little energy (and therefore producing very little heat).
     
  5. Mockletoy macrumors regular

    Mockletoy

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    #5
    That is for sure not normal. When the temp spikes like that, open up Activity Monitor and see what's hitting the CPU. Something has to be really hammering it for the temps to get that high.

    Or, there's something wrong with the cooling system, which, like others have said, involves cleaning the fans and making sure the vents are unobstructed, and maybe replacing the thermal paste. Also couldn't hurt to make sure that the heatsink assembly is properly tightened down.

    In your screenshot, it shows your fans running at ~4000rpm. I'm not sure about your particular model year machine, but I've had other MacBooks that would run the fans closer to 6000rpm (and sound like a hair dryer). May be nothing, but if there is some more oomph to be squeezed out of the fans, it could help a little.

    If all else fails, you could always try undervolting the CPU. I don't know if you know anything about that, but basically all CPUs are unique to some extent in their voltage requirements, some needing more, some needing less, but it would be prohibitively expensive and time consuming for Intel or AMD to figure out the optimum voltage for each individual CPU, so they set them to a sort of lowest (highest, really) common denominator at which they'll all reliably run and then ship them out the door. Which is to say, every CPU is running at the voltage of the crappiest, most power-hungry CPUs of a given generation, and Intel unfailingly errs on the side of too much voltage in the name of maximum stability. As an example, a -0.125mv undervolt on my gaming laptop's 7700HQ CPU is (so far) 100% stable and is the difference between the CPU being able to run at full turbo indefinitely vs. thermal throttling and dropping the clockspeeds. A good undervolt can generally net you a 5-10C temp drop at max load, more if you're very lucky. It also, naturally, gives you a little bump in battery life.

    I used to undervolt my old Core2Duo MacBook Pro and it was the difference between usability and constant thermal throttling and roaring fans. That said, I haven't tried to undervolt a modern Mac, but a quick Google search turned this up:

    https://www.reddit.com/r/apple/comments/5rl7x9/volta_ultimate_power_control_for_mac/

    I don't know anything about that software, or the developer, or how well it may or may not work, but it could be a starting point.
     
  6. jerryk macrumors 601

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    #6
    Are you using an external monitor? External monitors use the integrated GPU generating heat.
     
  7. Queen6 macrumors 604

    Queen6

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    #7
    On the video side the content may not be decoded in hardware hence the very high temperatures, nor much that you can do with it. The notebook will likely benefit from the fans and heatsync being cleaned up as with such high temp and middling CPU usage something is off.

    The external display may also push the iGPU harder. I still have 2014 13" rMBP kicking about that I mostly just use for media playback attached to a 34" 2K Ultraswide and it rarely passes 70C. Is the player using Flash as that will send the temp through the roof on a Mac guranteed.

    Q-6
     
  8. imrazor, Mar 16, 2018
    Last edited: Mar 16, 2018

    imrazor thread starter macrumors regular

    imrazor

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    #8
    Thanks for all the input. So this is a Youtube video playing in either Safari or Firefox Quantum. One thing I've noticed is that the initial transition between windowed and full-screen modes generates a *lot* of heat. That animation hammers my iGPU for some reason. Since it's Youtube, I assume it's HTML5. I assume both Safari and Firefox are able to apply hardware acceleration to a Youtube/HTML5 video. I doubt it is using Flash.

    I am using an external monitor because the internal display is physically damaged. However, the external display is a 1080p monitor whereas the internal display is 2560x1600p, so it would seem odd to me that a lower resolution display would generate more heat than the Retina display.

    I did blow out the external vent & exhaust, but I don't have a Pentalobe driver handy to remove the bottom of the chassis. The most helpful thing I've done is install "Macs Fan Control" and set up a more aggressive fan curve. That got me down to about 80ºC for full screen playback.

    I've overvolted PC CPUs while trying to overclock, but I've not tried undervolting. I've read that it can cause instability. I guess it'd be a process like testing for overclocking stability. Is there a stress test available for Macs like AIDA64 or Prime95?

    Further suggestions welcome. I'm about to order a Pentalobe tool from iFixit.

    EDIT: I had a couple of other thoughts about this. Would using a USB to Ethernet adapter cause extra heat to be generated? Does having the lid closed increase heat? What is the “CPU Proximity” sensor – it seems to be much lower than the Core 1/Core 2 sensors?
     
  9. Queen6 macrumors 604

    Queen6

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    #9
    You can source an App that disables the Turbo Boost in OSX, however I'm not aware of any way to Undervolt the CPU. Windows there are several applications that allow the same. Instability only occurs if you reduce the CPU Core & Cache voltages too deeply with the benefits of CPU Undervolting far outweighing any negative.

    Closing the lid should have negligible impact on the cooling of the CPU as it's a sealed circuit. CPU Core temp will always be higher than CPU Proximity as the sensor is from my understanding not directly on the CPU die.

    Q-6
     
  10. jerryk macrumors 601

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    #10
    Macs use the GPU all the time when displaying to external monitors. They do not use the GPU as often (only when doing graphics operations not handled by display circuitry) when using the main display.
     
  11. duervo, Mar 18, 2018
    Last edited: Mar 19, 2018

    duervo macrumors 68020

    duervo

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    #11

    Your system doesn’t have a dGPU. A 13” 2012 retina system only uses integrated graphics. Using an external display with it shouldn’t cause the CPU temperature to go up.

    CPU Proximity is the heat sink for the CPU.

    The difference between CPU Die and CPU Proximity gives you a hint at the performance level you’re getting from thermal transfer between them. Larger the diff, worse the performance.

    ie: My mid2011 Mac mini has a delta of 4C between CPU Die and CPU Proximity. The GPU Die and Proximity has a delta of 3C. I reapplied the thermal paste about 18 months ago in that system.

    I don’t have a mid2012 13” Retina system with which to test, so I can’t say for certain, but the delta for your system seems rather high. You could try to reapply thermal paste and see if that helps, but TBH, you have a used system that has been physically damaged, so there could be other things going on that are not readily apparent without a visual inspection of the logic board by a more qualified person.
     
  12. imrazor thread starter macrumors regular

    imrazor

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    #12
    I have a pentalobe driver on the way, which will allow to remove the bottom cover and inspect the logic board and cooling system. I plan to blow it out, but I'm not sure that'll be enough. I've reapplied thermal paste in PC laptops, but haven't tried it in a small Macbook. How difficult is it to get to the CPU? Is there a recommended brand of thermal paste?

    The seller also told me that the left USB port was flaky. Actually, it seems completely non-functional. The front-most Thunderbolt port *is* flaky, and only the rear TB port works reliably. Also weird stuff happens to Bluetooth and wifi when I plug in the TB port. I still need to try the audio jack and SD card. I'll see what kind of damage there is to the logic board once I get the pentalobe driver in a few days.

    In short, the system is *usable* as a Mac desktop, but I'm not sure it's worth investing a lot of money, effort or time into restoring it. It seems like I got my money's worth, though it does work as advertised.
     
  13. Toutou macrumors 6502a

    Toutou

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    #13
    Please don't spread your own confusion about what a GPU does.
    A Mac uses a GPU all the time. macOS's UI has been hw accelerated since Jaguar or so, which means that the GPU is responsible for drawing nearly everything on your screen at any given moment.

    The only difference between using an internal/external screen exists when the MacBook is equipped with a dedicated GPU. In that case the dGPU is always used for drawing when an external screen is connected. Without an external screen, the OS switches between the iGPU and dGPU to conserve power when possible.
     
  14. duervo macrumors 68020

    duervo

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    #14
    Yikes. If it were me, I’d just redo the thermal paste, and use it as is then. For a system that’s over 5 years old at this point, I’d hesitate to spend potentially significant time and money on fixing all those issues.

    I used Arctic Silver 5 thermal paste for my system. There is a cure time for it before its effectiveness normalizes. The manufacturer states up to 200hrs of normal use, which includes shutdowns for periods long enough to let things cool down (ie: Use it during day and have it off over night.) But, with that, YMMV. I don’t think I’ve ever had to go very long before the temperatures normalized. Usually takes no more than a day or two for me.
     
  15. imrazor thread starter macrumors regular

    imrazor

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    #15
    So I finally got the pentalobe driver (took a couple of days longer than I thought), removed the bottom cover of the Macbook and blew out the vents and fans. Now temps hover around 75ºC - 78ºC when playing an HD video, but they still spike up to 90ºC when the video first loads. That doesn't sound like much of an improvement, but I also tried another test.

    My Cinebench R15 score went from 209 to 246, which is a substantial improvement in performance. The extra cooling performance must have alleviated some of the thermal throttling I was seeing. Anyone know what Cinebench R15 score I should expect with an i5-3210M that's not getting throttled at all?

    I'm not sure I want to try re-applying the thermal paste. Those bloody screws are microscopic...
     
  16. imrazor thread starter macrumors regular

    imrazor

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    #16
    I failed to realize that the ambient temperature was about 5ºC below normal, skewing my results. After warming up the room, the Cinebench score dropped to 217. Better, but not as good as it should be. So I decided to go ahead and re-paste.

    The screws were a fair bit smaller than the ones I usually find in Dell laptops, but I managed the disassembly without losing any hardware. However, after re-pasting the temperatures just don't seem that much better. I'm still hitting 83ºC while watching videos, though it's 10ºC - 12ºC cooler than when I started this project.

    Another pass with Cinebench netted a score of 232. Also, better than the 209 I was getting at the beginning, but still short of the 246 I saw when the room was cold. Is throttling normal with a Retina MBP when running something as demanding as Cinebench?

    I'm still seeing a large delta between the CPU Proximity sensor and the Core 1/2 sensors. It's still about 13ºC, no different than the numbers I posted in previous posts. So it seems there's something fundamentally wrong with the cooling system. I'd say it's not worth repairing the display.
     
  17. impulse462 macrumors 68000

    impulse462

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    #17
    Yeah those numbers you’re getting are still way too high. I did some testing on a friends 2015 mbp 13” and his computer is at 46-53c watching hd video. Seems like something is wrong with the heat sink or cooling system in general
     
  18. duervo macrumors 68020

    duervo

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    #18
    I never ran Cinebench R15 before, so not sure if I did it right. I just clicked the "Run" button next to each of the test (OpenGL and CPU.)

    Here are my results on my mid2012 Unibody 15" i7 Macbook Pro.

    Screen Shot 2018-03-22 at 9.12.56 PM.png

    Temps & Fans.png

    Temps and Fans are expected given the workload at the time (Cinebench,) but once the benchmark is finished it all drops back to normal.
     
  19. imrazor thread starter macrumors regular

    imrazor

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    #19
    @duervo Well, your i7 is almost exactly twice as powerful (double the cores and threads, and almost the same speed) as my i5-3210m. So 246 seems about right...

    @impulse462 In the past, I had cooling issues with my old 2007 iMac. It was an uncommon problem, but apparently the fluid (or maybe it was a gas) could leak out of the heatpipe and cause high temps. If something similar has happened to this MBP, could replacing the heatpipe+heatsink fix the problem?
     
  20. duervo, Mar 22, 2018
    Last edited: Mar 22, 2018

    duervo macrumors 68020

    duervo

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    #20
    Yeah, I know. Just figured it would help for comparison, that's all.

    It's possible that a cracked heatsink or pipe could explain the temperature difference between die and proximity. I usually check iFixit.com for Apple part numbers, and then Google that part number for a cheaper source, unless iFixit's price seems reasonable at the time.

    https://www.ifixit.com/Store/Mac/Ma...na-Late-2012-Early-2013-Heat-Sink/IF123-014-1

    Apple Part #: 923-0227
     
  21. imrazor thread starter macrumors regular

    imrazor

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    #21
    Found one marked as "new" on eBay from a "top-rated seller" for half the price. But it won't get here until next week. I'll post my results once I get the new part.
     
  22. imrazor thread starter macrumors regular

    imrazor

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    #22
    Success! I got the heatsink/heatpipe in today and installed it. Now when I play videos the temperature runs between 58ºC and 66ºC. I did a Cinebench R15 run and got a score of 249, and the temperature maxed out at 85ºC. That is a major improvement, though I think the temps are still a little high.

    Now I need to figure out if I'm brave enough to try an LCD replacement. In any event, it'll have to wait until the next paycheck. Those Apple displays are bloody expensive.
     
  23. alecgold macrumors 65816

    alecgold

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    #23
    Thanks for the update!
    Nice to read it did work.
    Those old Macbook's can still do decent home-stuff.
    I opened up the Macbook (first unibody, I think 2008?) of my mother-in-law a few weeks ago and there was a felt blanket of dust on the out-side of the fan. It really made a lot of difference for the temperature and fan-noise.
     

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