Thermals Explored: 2012 rMBP and MBP

Discussion in 'MacBook Pro' started by Evil Spoonman, Jul 1, 2012.

  1. Evil Spoonman macrumors 6502

    Jan 21, 2011
    When the new Retina MacBook Pro launched, Apple had this image floating around which displayed the extra intake vents and new cooling system layout. Those of us who push our MacBook Pros hard are very aware of the space-heater quality they take on. Did the new chassis fix this?

    Apple updated the old chassis with Kepler and IVB alongside the new Retina model. While all the focus was on the Retina, I've not seen anybody pit the chassis against each other to see whether it was the new parts that caused a thermal improvement, or the revised cooling system.

    To cut the suspense short, the Retina MacBook Pro is substantially cooler under my testing. Read on for details.

    Up until a year ago I lived in the San Francisco Bay Area, and would zip over to Apple Store Palo Alto when something new and shiny launched to run tests. Since then I have moved to Adelaide, Australia. There is no Apple Store here, and all of the retailers tend to get new shiny toys quite awhile after launch. I attempted to crowdsource this data from the MacRumors community, but nobody supplied anything more than anecdotal evidence (thanks regardless). Recently, Myer at Marion got a Retina model in, and I pounced on the chance to irritate the staff there by running their machines very hot and loud.

    The models tested...
    - Base model Retina MacBook Pro - 2.3GHz IVB, 8GB RAM, Nvidia GT 650M (1GB), 256GB SSD.
    - Base model traditional MacBook Pro 15" - 2.3GHz IVB, 4GB RAM, Nvidia GT 650M (512MB), 500GB 5400RPM HD.

    These are not the higher-shelf machines, but they are close enough to compare like-for-like.

    The testing methodology...
    - Install and run Temperature Monitor. Specify CPU Temp Diode, dGPU Temp Diode, and Left Palmwrest sensors, then apply these to the chart.
    - Launch Activity Monitor and display CPU History to be sure all threads were fully utilised.
    - Launch OpenGL Driver Monitor. Attach it to the GT 650M. Monitor parameters GPU Core Utilization and CPU Memory Utilization. To make sure that the GPU is being stressed.
    - Launch Prime95 and set up five torture test workers.
    - Launch SmallluxGPU, set up the Glasstable scene, using GPU only, at 1024x768, and run it in interactive mode.
    - Use Quartz Debug to confirm that the Nvidia GPU was being used.

    I had some concern about SmallluxGPU not properly utilising the new GPU, but it seemed to identify and use it just fine. I also was not fully sure that Temperature Monitor would work properly on the rMBP, but it seems like the sensors it is reading work properly.

    The results...

    - The rMBP's fans seemed to ramp up sooner. As soon as the GPU got to ~87 C the fans starting ramping and were able to bring the GPU temp down to a stable 80 C.

    - In the older chassis, the fans waited until the GPU temp was quite high, about 95 C, before ramping up. They then brought the GPU down to a stable 90C. That's a full ten degrees hotter than the Retina MBP.

    - CPU temperature in the classic MBP chassis settled around 76 C. In the rMBP, the temperature was 66 C. Again, a 10 degree difference in favour of the Retina chassis.

    - I played a bit with the Prime95 worker count in order to get the highest possible utilisation across both CPU and GPU. Five workers was generally the best balance allowing 98% CPU and 80-90% GPU. If too many CPU cycles went into Prime, GPU utilization dropped considerably.

    - Both machines improve markedly from last year, largely on the laurels of Ivy Bridge's and Kepler's efficiency. Thanks Intel and Nvidia. However, the Retina chassis appears to allow better (and more responsive) cooling.

    - On the classic unibody MBP, set to four Prime workers, I was able to achieve ~90% GPU utilization. However, the CPU was then around 85% total utilization. When I set Prime to five workers, GPU utilization dropped to around 85%, but the CPU was at 100%.

    - On the Retina MacBook Pro, I was able to maintain five Prime workers and ~90% on the GPU. I am not sure why this is - theoretically the compute is identical. System memory is probably the differentiating factor.

    - I was not able to read or set fan speeds due to not being able to install SMCFanControl without an Admin password, which I did not have.

    Attached images... (see bottom of post)

    - Retina MacBook Pro Fan Ramp and Last Generation MacBook Pro Fan Ramp
    These charts are interesting. It appears that the Retina MacBook Pro is able to respond to more points on the temperature curve than the older MacBook Pro.

    The older MacBook Pro lets the temperature climb very high, then it engages the fans at their full ~6,000RPM and brings the temperature back down quickly.

    The Retina MacBook Pro appears to spin the fans at progressively higher RPMs as the machine gets hotter. This makes the temperature gain more gradual. All the dips in the rMBP's chart are me starting and stopping Prime quickly to try and adjust worker counts. It makes the chart a bit less accurate.​

    - Retina MacBook Pro and Last Generation MacBook Pro Process Utilization and Info
    A status point to note as I finished up the test. Showing various metrics and info on both machines.

    - Retina MacBook Pro Desktop image
    This is just a shot showing the environment I tested in. I had the rMBP set to 1920x1200 (doubled) for maximum desktop space. It was very usable and excellent.

    Any questions or comments, don't hesitate. Cheers!

    Attached Files:

  2. skitzogreg macrumors 6502


    Oct 31, 2007
    This is actually better news for the cMBP than the rMBP. We expected awesome thermals in the rMBP, but I don't think anyone thought the cMBP would improve the thermals to the point of not creating a burning brick.
  3. Exana macrumors regular

    Mar 15, 2011
  4. magbarn macrumors 68000

    Oct 25, 2008
    Thanks for the excellent post. I wonder if there's a throttling mechanism that's holding back the GPU/CPU when a certain total system power mark is exceeded? How were the noise levels BTW? Is the rMBP 'variable ratio' fans all they're cracked up to be?
  5. Exana macrumors regular

    Mar 15, 2011
    My MacBook Pro 15,4 2,6 GHz 2012 do throttle when running Prime95 and FurMark with Windows 7 64bit. It doesn't while playing Skyrim.
  6. Evil Spoonman thread starter macrumors 6502

    Jan 21, 2011
    While I agree that this is good news for the cMBP, I don't feel that it was at all a sure thing that the rMBP would have better thermals. Since the PowerBook Apple has demonstrated that they don't mind making space heaters at the expense of noise. However, I am really glad to see that the rMBP's thermals are indeed markedly improved. I'd still hesitate to call them awesome.

    If the system were to exceed a certain temperature, probably somewhere around 95C, it would begin to throttle down CPU performance definitely, and possibly GPU performance as well. I did not see throttling in probably 30 minutes on either system, so it is possible that the throttling issue Anand discussed with the 2011 MBP has been fixed by the lower power IVB and Kepler parts. However, the post quoted below says that under an unrealistic synthetic workload that is not the case.

    Fan noise was not really that different. It sounded more like whooshing air than spinning fans. Still plenty loud, even in a fairly crowded department store. Then again, so was the classic MBP without the new fan design. I don't think it's that big a deal. At lower speeds it matters more, rMBP's fans are almost impossible to hear.

  7. KingArthurVI macrumors regular


    Dec 17, 2011
    Minneapolis, MN
    For me, the fan's noise level is still pretty high IMO. Too loud for my liking :p can't expect 100% comfortable gaming experience with a notebook computer I guess.
  8. pacman7331 macrumors regular


    Apr 5, 2006
  9. M5RahuL macrumors 68030


    Aug 1, 2009
    Great job OP. One of the reasons I returned the 2011 15" MBP was heat. I usually use my laptop.. on my laptop! :p The 2011s would heat up significantly, so I switched to the 13" MBP and it was much more comfortable.

    However, my two day old Mid 2012 15" MBP runs quite cool and nowhere near as warm as the 2011. I got the base model MBP [ 2.3 / 4 GB / 500 GB HDD / 650m w.512MB ]

    So far, I'm extremely happy with this laptop! :apple:
  10. Sadisterr macrumors member

    Sep 1, 2013
    To OP:
    CPU proximity temperature in graphs you posted and stated as CPU temperature itself s not really the real CPU (cores!) temperature! If proximity is about 76C as in your graphs, the real CPU temperature will be around 100C!
    The temps you posted are actually quite high and heating up like most of the MBPs. 90C for GPU is quite high too (core temp here is correct).

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