iMac Retina 5K SUPER HOT

Discussion in 'iMac' started by dasx, May 2, 2017.

  1. dasx macrumors 65816

    dasx

    Joined:
    Jun 18, 2012
    Location:
    Barcelona
    #1
    Hi!

    I use my 5K Retina iMac (i7 4Ghz + Radeon M295X) to edit 4K video. Probably 8h a day of editing + 4h exporting. I bought it in January 2015 (was doing 1080p back then) and worked great.

    With the jump to 4K and the computer over 2 years already, it start to be slower, but what really worries me is that the GPU is constantly -when exporting- between 103 and 107ºC (217 - 225ºF) and sometimes it will reach 111ºC. When that happens, screen goes back and everything pauses, even fans, for like 5 seconds. Everything comes back but unless I manually abort the export in FCPX, it will try to keep going, 111ºC again and same process.

    Computer is out of warranty, I completely forgot to purchase Apple Care so there's that.

    What can I do?

    Thanks.
     
  2. Stacc macrumors 6502a

    Joined:
    Jun 22, 2005
    #2
    Your GPU shouldn't be getting over 100 degrees C. Try and document that and especially the pausing and freezing and then contact Apple.
     
  3. Bertrude macrumors member

    Bertrude

    Joined:
    Aug 2, 2010
    Location:
    England
    #3
    I don't know what the consumer law is like in Spain but in the UK there's a claim period of 6 years (from date of delivery) within which you can get repairs etc if the item is defective etc.

    I was lucky enough to get my 2011 iMac GPU replaced under this law. Maybe there's something similar under Spanish law too?

    You could perhaps start using some fan control software to help reduce temperatures under load by running the fans quicker. I've found it handy when gaming etc on my iMac. I've been using smcfancontrol.
     
  4. Lunder89 macrumors regular

    Lunder89

    Joined:
    Oct 16, 2014
    Location:
    Denmark
    #4
    I am afraid it is well known the 2014 iMac 5k runs a little hot. It actually needs to turn down the performance of the GPU and CPU in order to keep itself from burning up.

    A GPU above 100 C, is not uncommon, but above 110 C is a little out of the ordinary.

    If the computer is closing in on 2 years of age, it might have a lot of dust in the vent. Have you tried compressed air on a can, to get some of the dust out? (Just blowing compressed air into the fan vents, while the Mac is off)
     
  5. Malus120, May 2, 2017
    Last edited: May 3, 2017

    Malus120 macrumors regular

    Joined:
    Jun 28, 2002
    #5
    Use SMCFanControl (link below) to just keep your system fans maxed all the time. This isn't ideal from an acoustic standpoint but it should help keep your computer from hitting its thermal ceiling.

    (https://www.eidac.de)

    Since you're in Barcelona make sure you have the AC on when you're doing anything intensive and turn it up!

    You need to be carful because anything beyond 107C is actually rather dangerous (this is why the machine temporarily stops when hitting 110C so as to avoid damaging the components).

    Ideally you could take it to the Apple Store and at least see if they can diagnose the problem and give you an estimate. If you purchased with a credit card it may offer another year (or more) of extended warranty so be sure to check. If that is the case then have Apple repair it and then just bill the CC company for whatever Apple charges you.

    Unfortunately this is untrue of the maxed out (4Ghz/M295X) 2014 Retina iMac models. It is "normal" for the CPUs and GPUs in these models to reach 107C when under heavy load (particularly combined CPU/GPU load). This is part of the reason I sold mine as I wasn't comfortable with that kind of heat long term.

    Up to 107C (the point at which these machines begin to throttle) is not uncommon, but anything above that (110C!!!!) is in my experience out of the ordinary. The OP lives in a hot climate, but I wouldn't be comfortable with it hitting those kind of temps on a regular basis and the blackouts confirm this is not normal behavior.

    Cleaning out the fan may indeed help as the computer is designed to throttle so as not to exceed 107C...
     
  6. dasx thread starter macrumors 65816

    dasx

    Joined:
    Jun 18, 2012
    Location:
    Barcelona
    #6
    As Malus states below, it is sad but it is normal with the Retina iMac, at least the 2014 and a maxed out one. I was getting ~105ºC since day one, these super high temps have been happening more lately.

    Apple offers 1 year without Apple Care. Spain law's makes it so they have to offer 2 years, but that too expired last January, I didn't have this issues until like 1 or 2 months ago. :(

    I have been using iStats since I bought the iMac. It lets me monitor temps in the task bar and also allows for fan control. If I set them to max before starting to export, it takes a little longer but in ends up getting at 105 - 107ºC no matter what. Then, maybe, and sometimes, it'll reach more and start the issues.

    Haven't tried that actually. I tried a vacuum cleaner accessory that is kind of a tube and put it right in the back grill (where the hot air comes out from), but didn't really seem to get much out of it.

    Having a lot of dust inside of it is definitely a possibility, now is when I hate that you can't easily open up an iMac.

    Yeah, during summer time I must turn AC ON, no doubts. As for taking it to the Apple Store, problem is I'd be several days without the computer and I need it almost 24/7. Once I jumped to 4K I realized this 5K iMac hadn't been the best choice, I would've benefitted better from a Mac Pro I think, but I can't justify buying a 4 year-old computer at that price point, even with the... "price drops".

    My best chance is, I think, wait for this new Mac Pro they're allegedly working on, probably 2018, and hope for the best with my iMac.

    Thank you all!
     
  7. Malus120, May 3, 2017
    Last edited: May 3, 2017

    Malus120 macrumors regular

    Joined:
    Jun 28, 2002
    #7
    Damn seems like you've already tried all of the standard solutions.

    Here are some other, more drastic steps I thought of:
    1. Disable Turbo Boost: This will initially slow your machine down a bit (no boosting to 4.4Ghz), but given that the 2014 models already throttle down their base clock of 4Ghz when they hit 107C, this shouldn't hurt performance too much while allowing the chip to stay cooler.

    2. Disable Hyper Threading: Given your use case, this could have a more dramatic impact on performance, but may (emphasis on the may, I've never tried this) also help the chip to stay cooler as it will be doing less work.

    3. Underclock/Undervolt the GPU: This one's pretty extreme and I'm not sure it's even possible, but if you can get the GPU to use less power that should have a massive impact on the amount of heat generated. Again, I have NOT tried this but theoretically it MIGHT be possible using something similar to the following procedure:

    A. Backup macOS and then install the Clover Bootloader (normally used for for hackintoshes) onto a blank EFI partition on a bootable drive.

    B. Either via Bootcamp or Clover, install Windows (the latest Windows 10 insider preview will work if you don't have a license)

    C. Dump your GPU's BIOS file (various overclocking utilities such as MSI Afterburner/Sapphire Trixxx will allow you to do this)

    D. Edit your GPU's BIOS file to lower the core clockspeed and or slightly undervolt the various power states (look this up if you don't know what it means) (Look for a guide on Tonga BIOS editing, and pray that the Mac BIOS has similar values)

    E. Save the edited BIOS to the Clover EFI partition (DON'T FLASH IT BACK TO YOUR CARD!), and use the Clover vBios function to have Clover run your graphics card with the modified bios (without overwriting or otherwise modifying your cards actual BIOS)

    Just to be clear, while I don't know if the above will work (I don't know if Clover's vBIOS function will work with a real mac / whether or not the BIOS Apple has on the card is similar enough to the desktop R9 285 for any PC BIOS editing guides to be applicable) there shouldn't be any serious risk to the machine as you're not actually modifying the BIOS file on your graphics card. If you've never built a hackintosh or messed with GPU overclocking/bios editing on Windows, its probably going to be a lot to take in. That said, if you're interested in giving it a shot I can point you in the right direction.

    4. Edit the AMD Graphics Driver Kexts in macOS to disable GPU compute units: This is a slightly less extreme than #3 but the principal is similar. The eGPU/Hackintosh community recently figured out how to modify the macOS AMD Graphics Driver Kexts to remove the compute unit (CU) limit on officially unsupported cards (the R9 Fury/R9 4xx series). These cards were previously limited to 16 CUs (the number of CUs the R9 460, the only officially supported "new" AMD card had), but can now access between 32-64 (depending on the card. While I'm pretty sure the Kext mods currently known only work on the Kexts for the latest AMD cards, if you could find a similar hack for the "Tonga" class of cards (M295X/M395X), you might be able to disable a few CUs and reduce the heat output (at the cost of performance). Again, I can point you in the right direction if you're interested, although it's probably a bit of a long shot.

    5. Get an eGPU and an External Monitor: This will be expensive, but should allow you to relieve the strain on the iMac's internal cooling system. That said, Final Cut doesn't always play well with multiple GPUs (outside of a real cMP/nMP), so you should definitely check with the eGPU community first for advice. Also, I believe using an eGPU with the 5K iMac requires a hack which limits the resolution of the internal screen to 4K (although this may have been resolved, I haven't checked lately)

    Anyway, food for thought. I'd really recomend you do whatever you can to get those temps down, otherwise your iMac may not last until the nnMP/2017 iMacs....
     
  8. Fishrrman macrumors G4

    Joined:
    Feb 20, 2009
    #8
    Is there any way to deliberately "throttle back" the CPU/GPU on the Mac OS?
    In other words, "limit" it to running at 80-85% of full power under certain apps?

    Processing time would increase slightly, but by keeping the GPU/CPU from going to "full", it might keep the heat reduced somewhat...
     
  9. Stacc macrumors 6502a

    Joined:
    Jun 22, 2005
    #9
    Woah, I always understood the conventional limit to be 100 C. Thats ridiculous. I think they addressed this somewhat in the 2015 model, hopefully they go further in this year's model.
     
  10. Crosscreek macrumors 68030

    Crosscreek

    Joined:
    Nov 19, 2013
    Location:
    Margarittaville
    #10
    That's crazy hot compared to my hack that is overclocked to 4.7GHz with a Nvidia 1070 GPU. It never goes over 70C at 100% CPU on Handbrake. Even running games at 4K on it with the GPU OC it holds at 70C on the GPU. I'm surprised the solder and MB tolerate that heat but I guess that's Apple engineering.
     
  11. dasx thread starter macrumors 65816

    dasx

    Joined:
    Jun 18, 2012
    Location:
    Barcelona
    #11
    Wow, amazing, thank you very much. I would definitely try it out, everything, but it's my main rig for work and as a freelancer I work like 14h/day 24/7 almost, so it's difficult to assume all that risk.

    If the thing goes worse and worse I'll end up trying it, but for the time being I don't think I can assume such a risk.

    Anyways, thanks a lot! If I ever decide to do it, I'll come back for your advice :)

    I considered the hackintosh way, but yet again, this a work rig. I need it to run as perfectly as possible, with updates and all. I can't spend all that time making it work properly. Plus, I work with mac because of FCPX. When working with h264 it outperforms any other software. And in the macOS and FCPX world, NVidia seems to have some kind of problem... AMD cards work soooo much better.
     
  12. Crosscreek macrumors 68030

    Crosscreek

    Joined:
    Nov 19, 2013
    Location:
    Margarittaville
    #12
    Yeah, I was just commenting on your temp issue. I agree if it's a work rig and since AMD cards have issues used in hackintoshes you are better off with Apple.
    I'm just astonished that your iMac gets that hot without shutting down.
     
  13. shaunp macrumors 65816

    Joined:
    Nov 5, 2010
    #13
    This is the issue I've always seen with the iMac, it has to throttle back under load because it has insufficient cooling for heavy workloads that would traditionally be run on a workstation. The Mac Pro is better in this respect (but completely dated). Honestly I would consider your workflow an if this is costing you money. Could it be done on Premier? (I'm not a video editor, I'm just suggesting an option). If it can be done on Premier then swapping to a PC would give you better performance and the hardware won't need to scale back because of thermal limitations. Just saying if it's costing you money then consider the options, it's not a Mac vs. PC debate, but a discussion on the best way to resolve your issue on the long-term.
     
  14. dasx thread starter macrumors 65816

    dasx

    Joined:
    Jun 18, 2012
    Location:
    Barcelona
    #14
    Yeah... I guess I got used to it, but I swear, day 0 after buying and first export BAM, 105ºC on GPU. I googled it, seemed normal, so forgot about it. Problem is when it goes beyond that and causes issues.

    It's weird because it'll happen occasionally. I might leave it exporting five different 4K videos overnight and everything is OK. I might be exporting + photoshoping + copying files and surfing the web and everything is fine. But then, randomly, temp goes up and thing "crashes" (not really a crash but still).

    Maybe, just maybe, the GPU throttling fails ever now and then and it's that what causes it, I don't know.

    I've considered it, yes. I'm a fast learner, I could in theory switch to Premier without crying too much. It'd be difficult and a learning process, but I could.

    Problem is when you compare the two performance wise. A top of the line HP Workstation with Premiere will be blown away by my iMac and FCPX in everything that I need it for. I import footage and convert to ProRes, FCPX wins by far. I then work with different effects, LUTs, chroma keys, slow and fast motion... Gotta say my iMac allows for real time scroll on the 4K footage, depending on the project Premier struggles a bit for what I've seen. And finally I export to h264. Workstations use Xeon chips, which don't support Quicksync (I still hope they implement it soon), which means my iMac has hardware CPU acceleration on that matters so kills the other machine. Even if you use Premiere con a CPU with quicksync, if I'm not mistaken Premier doesn't take advantage of it, so there's that.

    If you ever feel curious google some comparisons between Premier and FCPX ran in the same machine. It's crazy.
     
  15. fathergll macrumors 6502a

    Joined:
    Sep 3, 2014
    #15
    I wish I had a time machine to go back to late 2014 and show some users this thread as a "I told you so". This thread is exactly what people were trying to warn about a couple years ago and I distinctly remember certain posters here saying there was no issue with the iMac's thermal temps because the Apple engineers were much smarter than anyone of us and they designed the iMacs to 'handle' those temps. Lesson is always logically question things even from people who are much smarter than yourself. If your doctor gives you a diagnosis don't follow it blindly, make sure you really question it. If Apple releases cutting edge tech and you logically can't see it that tech being reliable long term then question it. Doesn't take a degree in hardware engineering to question the reliability of an all in one computer with 200ºF+ temps under load.
     
  16. shaunp macrumors 65816

    Joined:
    Nov 5, 2010
    #16
    That's interesting to know. I knew ProRes was a big deal, but as I don't work in that sector I've only an inkling as to why. I think a custom build PC with an i7 and a fast GPU would better suit your needs than a HP Z, but FCPX won't run on that unless you make it a Hackintosh.
     

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