Apple engineers reveal how they prevent Mac Pro overheating

Posted:
in General Discussion edited December 2019
Apple's new Mac Pro is the most powerful Mac ever made, and with that power comes extreme heat. To make the Mac Pro and the Pro Display XDR function, Apple engineers had to find new ways to handle those temperatures and keep the machine quiet.

How air is made to flow through the new Mac Pro
How air is made to flow through the new Mac Pro


The new Mac Pro and Pro Display XDR have distinctive Apple designs, but it's not for aesthetic reasons. Both inside and out, the new hardware design on both devices is built to keep the most powerful Mac in existence from overheating.

Speaking to Popular Mechanics, Apple's Chris Ligtenberg and John Ternus revealed some of how their work means the Mac Pro doesn't run too hot, and doesn't have loud fans.

The immediately-recognizable and already copied casing with its myriad holes is key to managing temperature for both the Mac Pro and in particular the Pro Display XDR, which can be used in both portrait and landscape.

"[The pattern] gives us a lot of surface area, which is hugely beneficial," said John Ternus, vice president of Hardware Engineering at Apple. "[For the Display] we wanted free [air] flow through the channels, no matter the orientation."

Close up of the lattice design of the Mac Pro case.
Close up of the lattice design of the Mac Pro case.


Part of that solution to dissipate heat regardless of whether the display was in portrait or landscape, was to make the holes hemispherical instead of round.

Ligtenberg, Senior Director of Product Design, explains that previously typical solutions to dissipating heat couldn't cut it.

"It's very easy to get air trapped in channels," he says. "A common solution, passively, is to have a finned enclosure, a heat sink. That was not possible."

Quiet fans

There are fans inside both the Mac Pro and the Pro Display XDR, but with the screen, they are solely to cool certain unspecified components. Ternus and Ligtenberg say that it is the bored metal holes that mean the LED panels can run brightly without problems.

They also say that the design of the holes means the Mac Pro itself gets "about 20 percent more airflow" than previous models.

However, the fans are not incidental. To help with the heat and to keep the Mac Pro quiet -- or just apparently quiet -- meant Apple had to design the fan blades especially.

Three Apple-designed fans pull air through the system
Three Apple-designed fans pull air through the system


"Years ago, we started redistributing the blades," says Ligtenberg. "They're still dynamically balanced, but they're actually randomized in terms of their BPF [blade pass frequency]. So you don't get huge harmonics that tend to be super annoying."

Reports so far say that the Mac Pro is exceptionally quiet. Beyond just quiet, Ternus says a big focus of the team was to make what noise it produces be simply less annoying.

"You can have something at a certain SPL [sound pressure level] that sounds really good," Ternus told Popular Mechanics, "But you can have something that's actually at a lower SPL that grates on your nerves and sounds really awful."

"We want to get really great performance where, you either can't hear it, or if you can hear it, it's kind of a pleasant noise," he continues. "A ton of analysis goes into figuring out how to optimize for that."

Apple's new Mac Pro is now available for pre-order, as is the Pro Display XDR.




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Comments

  • Reply 1 of 72
    cgWerkscgWerks Posts: 2,752member
    I wonder if some of that tech started in the 2018 Mac mini. While it can get noisy, I don't find the noise quite as irritating as I have past MBPs or especially some of the PC laptops (my wife's work-issue laptop drives me nuts when she brings it home and works on it).
    dysamoriarepressthiswatto_cobrarazorpit
  • Reply 2 of 72
    cgWerks said:
    I wonder if some of that tech started in the 2018 Mac mini. While it can get noisy, I don't find the noise quite as irritating as I have past MBPs or especially some of the PC laptops (my wife's work-issue laptop drives me nuts when she brings it home and works on it).
    I think it may even date as far back as the 2012 MacBook Pro. I recall one of those Jony Ive videos where he explained spacing the fan blades in such a way as to reduce the noise typically associated with cooling. 

    Looks like they’ve been perfecting this design ever since. 
    caladaniandysamoriacgWerkspscooter63sphericStrangeDaysfastasleeprepressthiswatto_cobraredgeminipa
  • Reply 3 of 72
    This is probably the most interesting article AI has ever published.  Fascinating. 

    And to state the obvious SOMEONE has to pay for all those man-years of research.  The $5K price is not all profit. 
    StrangeDayswatto_cobraredgeminipa
  • Reply 4 of 72
    cgWerkscgWerks Posts: 2,752member
    mr lizard said:
    I think it may even date as far back as the 2012 MacBook Pro. I recall one of those Jony Ive videos where he explained spacing the fan blades in such a way as to reduce the noise typically associated with cooling. 

    Looks like they’ve been perfecting this design ever since. 
    Yeah, maybe a steady improvement starting quite a way back. That said, I find my son's 2017 MBP fairly annoying, and that's only a year earlier than my mini. But, different form factor, I guess. They certainly improved the 16" MBP from the reports I've read.
    watto_cobra
  • Reply 5 of 72
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    pscooter63
  • Reply 6 of 72
    I know for a fact that electric radiator cooling fans in newer automobiles use the concept of random blades to help with noise.
    cgWerksStrangeDayswatto_cobra
  • Reply 7 of 72
    GG1GG1 Posts: 465member
    I know for a fact that electric radiator cooling fans in newer automobiles use the concept of random blades to help with noise.

    But do they have hemispherical holes? ;)

    I understand (superficially) the asymmetrical blade design, but the use of hemispherical vs. spherical holes? Wow. That is some serious attention to detail, or at least not leaving any stones unturned.
    minicoffeeStrangeDayswatto_cobra
  • Reply 8 of 72
    sjworld said:
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    Nope, not going to happen. 
    thtrepressthisnetmagewatto_cobra
  • Reply 9 of 72
    cgWerkscgWerks Posts: 2,752member
    GG1 said:
    But do they have hemispherical holes? ;) 
    Nah, but Elon is probably right on it. Think Cybertruck and let your imagination run wild.
    (What a comparison, huh... the Cybertruck has to be one of the worst designs of all time. I should probably be punished for mentioning the two in the same post.)
    randominternetpersonwatto_cobradavgreg
  • Reply 10 of 72
    sandorsandor Posts: 591member
    This is probably the most interesting article AI has ever published.  Fascinating. 

    And to state the obvious SOMEONE has to pay for all those man-years of research.  The $5K price is not all profit. 

    It is also the culmination of decades of consistent R&D.
    So the cost is spread over multiple years & dozens of projects, not just one machine.

    I would postulate that the G4/G5 era led to many thermal "finds" by Apple's R&D teams - we saw the quad nostrils, bigger, better fans, designed airflow, repositioning of other internal components, etc.

    ...he who stacks pork was a huge influence in my getting another 66 mhz out of my PowerMacs... long live xlr8yourmac.com !

    edited December 2019 mobirdwatto_cobra
  • Reply 11 of 72
    GG1GG1 Posts: 465member
    This is probably the most interesting article AI has ever published.  Fascinating. 

    And to state the obvious SOMEONE has to pay for all those man-years of research.  The $5K price is not all profit. 
    sjworld said:
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    I doubt Apple will reveal the upper limit of thermal capacity of this design, but there must be MUCH design margin after Apple admitted this shortcoming in the previous Mac Pro design.

    Can anybody estimate how much of the 1400 Watt power supply can actually be in use with all options and RAM installed?

    But a technical deep dive (from Apple) would be fascinating.

    Edit: grammar
    edited December 2019 watto_cobra
  • Reply 12 of 72
    Darn, wish I hadn't read this article. But now I just have to get this nnMP in order to hear it for myself.

    cgWerks
  • Reply 13 of 72
    wizard69wizard69 Posts: 13,377member
    sandor said:
    This is probably the most interesting article AI has ever published.  Fascinating. 

    And to state the obvious SOMEONE has to pay for all those man-years of research.  The $5K price is not all profit. 

    It is also the culmination of decades of consistent R&D.
    So the cost is spread over multiple years & dozens of projects, not just one machine.

    I would postulate that the G4/G5 era led to many thermal "finds" by Apple's R&D teams - we saw the quad nostrils, bigger, better fans, designed airflow, repositioning of other internal components, etc.

    ...he who stacks pork was a huge influence in my getting another 66 mhz out of my PowerMacs... long live xlr8yourmac.com !

    Apple may be taking credit for the fans but most likely the fan supplier had a big role in its design.   It is sort of like the mix between Apples IP and TSMC IP that gives us the high performance A series.    That isn’t to dismiss Apples engineering just that projects like these are collaborations between the suppliers and Apple.  
  • Reply 14 of 72
    A very effective way to even better manage thermals would be Threadripper. Double the performance, half the heat.
    watto_cobra
  • Reply 15 of 72
    wizard69wizard69 Posts: 13,377member
    GG1 said:
    This is probably the most interesting article AI has ever published.  Fascinating. 

    And to state the obvious SOMEONE has to pay for all those man-years of research.  The $5K price is not all profit. 
    sjworld said:
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    I doubt Apple will reveal the upper limit of thermal capacity of this design, but there must be MUCH design margin after Apple admitted this shortcoming in the previous Mac Pro design.

    Can anybody estimate how much of the 1400 Watt power supply can actually be in use with all options and RAM installed?

    But a technical deep dive (from Apple) would be fascinating.

    Edit: grammar
    The issue of power has the potential for along interesting discussion.  It is most interesting because Apple is still using Intel’s chips which soundly lost any power advantage they had to AMD.    So to get the performance they will have (which isn’t industry leading) they effectively will have to deal with a great deal of processor heat.   Then you have the video cards which are again hot.  So in some configurations you will easily see +500 watts for a single CPU chip and a high end GPU card.  Then there is Apples accelerator card which is likely going to be another hot zone.  

    What does this mean?   Well it is easy to see most of that power supply capacity being used.    Frankly we don’t know how much power is being budgeted per PCI-E slot but again you can easily expect +100  (probably a lot more) watt cards per slot.    I would expect many users to be running AI accelerator cards or compute cards in the box.   In the end a maxed out machine may not be anywhere near as quiet as a base line model.   Remember some of these third party cards have their own fans so no matter what Apple does fans will be an issue. 

    As for margin it is pretty hard not to throttle a CPU these days with out high performance cooling.     I’m certain somebody with deep pockets and time on their hands will he testing this new Mac Pro to see how well it does.   There is little to be said until the testing comes in.  
    GG1repressthiswatto_cobraviclauyyc
  • Reply 16 of 72
    Wgkrueger said:
    sjworld said:
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    Nope, not going to happen. 
    It's not "if" it's "when."  If I put 5 of these in a small enclosed office (with typical/poor HVAC) and run them full blast, at some point throttling has to enter the picture.  The question is whether under "normal conditions" in a "reasonable environment" a fully spec'ed out Mac Pro will able to run at full performance indefinitely.  I'm sure this was a big part of why it took so long to get these to market, so I'm optimistic that buyers will be pleased.  But we don't know yet.
    edited December 2019 sandorcgWerksFileMakerFellerwatto_cobra
  • Reply 17 of 72
    thttht Posts: 4,131member
    GG1 said:
    This is probably the most interesting article AI has ever published.  Fascinating. 

    And to state the obvious SOMEONE has to pay for all those man-years of research.  The $5K price is not all profit. 
    sjworld said:
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    I doubt Apple will reveal the upper limit of thermal capacity of this design, but there must be MUCH design margin after Apple admitted this shortcoming in the previous Mac Pro design.

    Can anybody estimate how much of the 1400 Watt power supply can actually be in use with all options and RAM installed?

    But a technical deep dive (from Apple) would be fascinating.

    Edit: grammar
    Apple says:

    Power Supply

    1.4 kilowatts

    • Maximum continuous power:
      • 1280W at 108–125V or 220–240V
      • 1180W at 100–107V

    Electrical and Operating Requirements

    • Line voltage: 100–125V AC at 12A; 220–240V AC at 6A
    • Frequency: 50Hz to 60Hz, single phase
    • Operating temperature: 50° to 95° F (10° to 35° C)
    • Storage temperature: –40° to 116° F (–40° to 47° C)
    • Relative humidity: 5% to 95% noncondensing
    • Maximum altitude: tested up to 16,400 feet (5000 meters)

    If these parameter ranges are square, the design case is running the machine at 16,500 ft altitude at ambient temperature of 95 °F with a sustained power delivery of 1280W. The dual Vega II card looks like it can hit about 470 Watts, and the Xeon CPUs have TDP of 205 W. 12 banks of RAM is probably less than 50 W. 1280W is just squeaking the maximum power consumption of the components. Cooling-wise, it will be dependent on the upper limit on how fast the fans can spin. If they designed it right, it will be fast enough to remove 1400 W of heat at 95 °F at 16400 feet altitude.

    It’s a bit esoteric though as it is pathological to max out both the CPUs and GPUs at the same time. The machine isn’t limited by thermals. They choose to design it for the typical 110 V 12 A circuit that are in the vast majority of places in the world. So it is limited by the typical power circuits in buildings. Higher power will mean some places will have to add higher power circuits, like the ones for a dryer or an oven. Then if you think about it, you do not want anymore than that for a machine that is on your desktop or desk side. It’ll heat up the room and you’ll need to have some consideration for the air conditioning the room.
    pscooter63GG1cgWerksmobirdwatto_cobraviclauyyc
  • Reply 18 of 72
    I don’t know why there’s such an uproar over the price tag. I had a small consultation business and bought a pair of two Mac llcis for a bit over $6,000 each, in 1992 USD. Didn’t complain as it was powerful and made money. Dropping, say, 10k$ on a workstation one could create a new “Jurassic Park” on is nothing to complain about. In the original movie the park was controlled by a Mac Quadra 700, which cost $6000, back then!
    StrangeDayswatto_cobradocno42
  • Reply 19 of 72
    thttht Posts: 4,131member
    I don’t know why there’s such an uproar over the price tag. I had a small consultation business and bought a pair of two Mac llcis for a bit over $6,000 each, in 1992 USD. Didn’t complain as it was powerful and made money. Dropping, say, 10k$ on a workstation one could create a new “Jurassic Park” on is nothing to complain about. In the original movie the park was controlled by a Mac Quadra 700, which cost $6000, back then!
    It’s the Internet where 90% of the comments are from trolls, wishful thinkers and increasingly bots (if you were on Twitter or Facebook). So, always keep that in mind.

    Nobody has even talked about the software that buyers of this machine have to pay for. Some of the software licenses will cost 10x the cost of the machine over its lifetime.
    cgWerksStrangeDaysfastasleepwatto_cobradocno42
  • Reply 20 of 72
    sjworld said:
    It’s air cooled. This machine is very much likely to start thermal throttling once it reaches 80C during heavy workloads.
    Ultimately all computers are air cooled. Liquid cooling gives additional heat-sink capacity and moves the heat to a radiator that releases the heat to the air.

    The Mac Pro's CPU Thermal module is quite large and has a dedicated fan so should radiate quite nicely.
    netmagewatto_cobra
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