Surface Pro 4 i7-6650U power throttling issue?

Discussion in 'Microsoft Surface Pro 4' started by theveterans, Nov 24, 2015.

  1. GreyFox7

    GreyFox7 Super Moderator Staff Member

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    That's not how this works.

    Power throttling is one of the techniques that can be employed to keep the CPU/GPU and other system temperatures under control. It's is not a lack of available power from the battery or charger rather it's a control mechanism.

    Battery charging is a separate issue and from my testing of the Surface 3 the charging circuitry will limit the max charge rate so using a higher powered charger does not speed up charging and I would expect the same behavior with the Surface Pros. There is an exception to this with the Surface 3 when using the docking station it charges through a different path an does charge at a higher rate. The Surface Pro's only have the Surface Connect to charge through so it's the same either way. The higher capacity chargers for the Book or the Dock are to provide power to other components like dGPU, extra fans, USB drives, etc.
     
  2. PumpkinPie

    PumpkinPie New Member

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    I know exactly what power throttling is, but it seems we have differing ideas about what's really causing it and whats going on here with the SP4. I'll just keep it simple and say that I think we'll see a dramatic difference once someone tests this with a SB's power supply.
     
    Last edited: Dec 20, 2015
  3. nonosbook

    nonosbook New Member

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    Hi all. This is my first post here so don't be too harsh :)

    The power throttling on the surface pro 4 is purely thermal.
    Having a more powerful adapter won't help and has been already tested by many people including myself (both with 65W charger and just connected to the new dock without any screens).

    The is a sensor on the top right corner that will automatically trigger PL1 once a certain temperature is reached.
    It doesn't matter if you lower your processor frequency as the sensor is using a ratio.
    For exemple :
    If i keep the TDP at 25w my surface will throttle when i reach 85 or 86C.
    if i force the TDP at 23w my surface will throttle when i reach 81C.
    If i force the TDP at 20w my surface will throttle when I reach 76C.

    The other proof that means it is purely sensor controlled is that when you apply an ice cube or ice bag in the upper right corner it will not throttle.
    I have done extensive tests and with ICE the TDP will stay at 25W potentially forever (I kept it 1 hour...) or until the ice melts and temperature rise again then it will immediately throttle.
    With the Fan "solution" you get around 18W to 19W (depending on the room temperature) but nowhere close to 25W.

    I have also tried all possible configurations in XTU or the new Throttlestop Beta 6 and nothing seems to be helping (reducing the frequency, untick PROCHOCT, lock the TDP...)

    The only thing that can be done is a bios hack to force the sensor to let the surface to higher in temperature as per discussed here : No more throttling for Surface Pro 3 :) | Microsoft Surface Forums
    I am not worrying too much about the temperature rise as the processor can easily go over 95C without any damage and setting up different powerplant allowing the processor to run up to a maximum percentage will always ensure the surface will run very cool when needed but will "turn" the surface into a tiny powerful light gaming station when plugged and in "performance" mode.

    I do not have the skills to extract and modify the bios to allow the same modifications to be done on the surface pro 4 (done by someone on the surface pro 3).

    Maybe someone more skilled than me could help ?

    Thank you !
     
  4. Mike007

    Mike007 Member

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    I'm more concerned with the fact that when the i7 is under load it will discharge the battery even when plugged in with the standard 36w charger.
    It drains quite quickly at about 25% per hour if I run games.

    You say you tried the 65w surface book adapter and the dock? Does this alleviate the battery discharging whilst under load?
     
  5. nonosbook

    nonosbook New Member

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    Yes, it does work. either the dock or the 65W prevent the battery from draining. Using max power like PRIME95 test it won't drain. So that's definitely worth it.

    When I had this issue in the very first days of my surface pro 4 i contacted the surface support and they agreed to send me a 65W charger for free. (I think i got very lucky).

    So with a combo of 65W/dock and a modded bios allowing to modify the sensor it is good.
    Let's hope someone is able to mod the bios...
     
  6. Mike007

    Mike007 Member

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    Seems to drain more when using the IGP as that drains a lot more power than just the CPU alone.
     
  7. nonosbook

    nonosbook New Member

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    I tried also in high demanding CPU/GPU games just to be sure. And yes, it does NOT drain
     
  8. Mike007

    Mike007 Member

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    That's good to know. Thanks for the tests.

    Now to wait for the release of the SB in UK so I can buy a 65w adapter.
     
  9. Ace64

    Ace64 New Member

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    Hi,
    New to the board. I see this thread is older, but ran across it as I'm considering a Surface Pro purchase.
    Re: the throttling issues and possible bios parameter modding;
    There is a similar thread that pertains to the Dell Venue 11 Pro (in my case, the 7139 model with an i5-4300y).
    Search for "Dell Venue 11 Pro throttling."
    It goes thru changing parameters by accessing the grub file. I was able to follow the directions and my unit does indeed run with less restriction than before the mods.
    Now, I was just following directions. So, I won't be able to answer technical questions. Please refer to the dell thread (it also links to a video) for a better understanding of what it does and if it could be applied to the Surface issue.

    Good luck all!
     

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