2018 MBP i9: Testing w/ Volta & Fan Control

Discussion in 'MacBook Pro' started by Aea, Jul 21, 2018.

  1. Aea macrumors 6502a

    Aea

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    #1
  2. mango316 macrumors regular

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  3. Standard macrumors regular

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    #3
    Thanks for this information and taking the time to do this. Nice pup you have there !
     
  4. winterny macrumors 6502

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    #4
    The throttling is not thermal as far as the CPU overheating ... It's power throttling because the VRM's that are powering the CPU are being overloaded, and overheating.

    When the VRM reaches it's maximum temperature, the system sends a signal to the CPU to drop it's multiplier to 1, which drops the clock speed to 800Mhz. VRM cools down, and it will then turboboost for a short time, overload the VRM again, and throttle again.

    The throttling back and forth is less efficient than just holding at a power draw rate which the VRM can handle.
     
  5. Aea thread starter macrumors 6502a

    Aea

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    #5
    The CPU is overheating. The CPU VRMs are overhearing.

    Those seem like splitting hairs. I don’t see how the latter isn’t a thermal throttle by another name.
     
  6. Feenician macrumors 601

    Feenician

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    #6
    Great analysis @Aea. Thanks a lot. I really wish Volta could be set with more granularity so we could see where the limits lie.
     
  7. winterny macrumors 6502

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    #7
    I make the distinction because even if you modify a 2018 i9 MBP by putting better Thermal Paste, it won't improve your performance because the VRM is being maxed out before the heatsink/fan/TIM setup.

    Also, if the CPU were being thermally throttled, it would hold a relatively steady clock speed rather than jumping from 800Mhz to full Turbo and back every couple of seconds, and the overall performance would be better if the CPU *was* thermally throttled.
     
  8. content, Jul 21, 2018
    Last edited: Jul 21, 2018

    content macrumors member

    content

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    #8
    Please correct me if I am wrong, but according to notebookcheck, there is a 13% gap between the mid model 6-core 2018, and the base model 4-core 2017. And by limiting power consumption to the processor on the 2018, this gap widens. The 2018 now sees 20% more performance. However, at the cost of closing the gap between the two when doing every day work that does not tax the processor. Further it appears, they would need to limit power consumption to the 2017 as well, to make the test completely fair. I mean, the gap may get close to 13% all over again, if they did this. If they applied the same tweak to the 2017 as well.


    And you have just shown that even when limiting the power consumption to the i9, it still has a worse score than the mid model 6-core 2018 with the same tweak. Ultimately making the i9 even closer in performance to the base model 4-core 2017. All without the same tweak applied to the base model 4-core 2017... Which may now make all of these tweaks meaningless to an extent?


    I am referring to:


    First article:


    https://www.notebookcheck.net/The-n...nd-clearly-beaten-by-the-XPS-15.317264.0.html


    Second article:


    https://www.notebookcheck.net/Apple...e-performance-with-a-few-clicks.317552.0.html
     
  9. Aea thread starter macrumors 6502a

    Aea

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    #9
    An apples to apples comparison would be running the machines at their best configurations.

    If that’s stock on the 2017 and power limited on the 2018 that should be fine.

    The tool I use does not have the ability to set a higher power limit from OSX. The actual ‘peak performance’ setting might be higher than 45W.
     
  10. joptimus macrumors newbie

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    #10
    Thanks for the review! Do you also have the 13“ model or only the one with the i9?
     
  11. ezerez macrumors newbie

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    Jul 21, 2018
    #11
    Thx for the review!

    I have i7-8850H and i also get alot better results in cinebench when i put 45W in Volta. cinebench gets around 950 and my cpu is stable at around 3ghz and around 85c. So there even seems to be some headroom! Would be great if i could put the limit higher then 45W to test. Maybe with another tool or if Volta gets an update?

    greets

    ezerez
     
  12. dylin macrumors 6502a

    dylin

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    #12
    Great information. Thanks for taking the time to run these tests :)
     
  13. SoyCapitanSoyCapitan macrumors 601

    SoyCapitanSoyCapitan

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    #13
    A desktop 8700K overclocked to 5GHZ gets 1650 Cinebench points for context. So laptops are not ideal for final CG rendering. Only pre-viz.
     
  14. shavou macrumors newbie

    shavou

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    #14
    Great test and amazing results, thank you very much!! I'm waiting for my i9 to be delivered next week and this results are very promising...I was 100% sure I wanted to return it for a i7 2.6 GHz but now after seeing your test I changed my mind.
    My 90% use would be photo editing, extensive batch processing in Lightroom and Photoshop with very large files (around 80MB each). Do you think I should always use Volta or just when performing the most demanding tasks?

    Also, have you seen this other software VoltageShift ? Probably with it we can limit the power above the 45w volta threshold...

    https://sitechprog.blogspot.com/2017/06/voltageshift.html?m=1
     
  15. The Mercurian macrumors 68000

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    #15
  16. Schranke macrumors 6502a

    Schranke

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    #16
    This is great @Aea thanks for doing this.
    Now the question becomes if apple will do a firmware update to change the values and set some limits...
     
  17. ofarlig macrumors regular

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    #17
    Great testing, looks good that much of it can be solved with software.
     
  18. The Mercurian macrumors 68000

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    #18
    One would assume they should - but.....I feel like they would not like to admit the users managed thermal management better than they did.....
     
  19. Schranke, Jul 22, 2018
    Last edited: Jul 22, 2018

    Schranke macrumors 6502a

    Schranke

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    #19
    I do not think apple will see it as users managing thermals better then them, but rather as a sign that they didn't test the machines enough before selling them. Apple should have found this, and they should know that their customers would too and that they will not accept it. So limiting power at different levels to see where it would perform best should have been done on a range of machines before.
     
  20. leman macrumors G3

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    #20
    Great stuff! (and thanks Mercurian for tagging me).

    I'd like to try it out as well, but the fact that this app is closed source is a dealbreaker for me. Does anyone know how this was achieved, maybe with some open source code?
     
  21. The Mercurian macrumors 68000

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    #21
    Opensource would also be nice because then presumably you wold not be stuck to 45W and could try 50W for example
     
  22. maflynn Moderator

    maflynn

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    #22
    I have no problems paying for an application that a developer worked hard on and given that Volta does exactly what I need, I'm happy to pay the small amount and reward the developer for his hard work.

    I'm not down on open source, but there's a time and place for everything and I think in this instance the closed source application is better then not having anything
     
  23. Schranke macrumors 6502a

    Schranke

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    #23
    Ohh I always love when people feel like that, it seems that more and more expect free application, not only on iOS but also MacOS.
     
  24. leman macrumors G3

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    #24
    Oh, don't misunderstand me, I will gladly pay for good quality apps, but I made a habit not to use system control apps like these if I can't review the code.
     
  25. CodeJoy macrumors 6502

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    #25
    Looks interesting, very good data collection. Can Volta only set the limit to 45W? What's encouraging is that power limit is something Apple could fix via firmware. What's potentially concerning is that there are physical limits both to power and to thermals in the current design, and neither is probably very easy to fix without a more significant rethink of the system.
     

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111 July 21, 2018