[Guide] Improving Battery Life on Windows [+Enabling Deeper C States]

Discussion in 'Windows OS and Software' started by Che0063, Apr 14, 2018.

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What was your increase in battery life after following this guide?

  1. None (decreased)

    17.1%
  2. 20%

    14.3%
  3. 40%

    31.4%
  4. 50% +

    37.1%
  1. viktor5001

    viktor5001 Notebook Enthusiast

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    I checked again and removing the hub(USB mouse and a cooling pad are connected to it) did allow the package power to go down to 0.6W instead of 0.7W. USB Selective Suspend doesn't seem to be working.
    Regarding PCI-E Suspend, do you mean PCI-E ASPM? That is disabled and I could not find much info regarding it.
     

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  2. IntelUser

    IntelUser Notebook Deity

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    Exactly that. There's a Lenovo thread discussing it.

    That CPU package state is pretty close to the lowest it'll go. But PCI-Express ASPM will drop non-CPU power.

    I know Intel platforms can afford to do better because ARM Windows systems do it. Also, their Tablet oriented Z-Atom platforms did comparably to ARM devices.
     
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  3. viktor5001

    viktor5001 Notebook Enthusiast

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    @IntelUser Is this http://forum.notebookreview.com/thr...ws-for-saving-2w-of-power-consumption.606100/ the one you were referring? I checked with HWInfo and ASPM doesn't seem to be enabled only for the Intel iGPU. Considering how little power it consumes when idle I wonder if its worth the effort to get it working? Getting USB Selective Suspend to work properly might be more beneficial I think.
    Edit: After a clean boot min. package power fell to 0.5W which as of now is the lowest ever. Still can't get USB Selective Suspend to actually work.
     
    Last edited: Jun 3, 2020
  4. Griffin3567

    Griffin3567 Notebook Enthusiast

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    Do I need to get my cstates sorted? Definitely not majority in 7 8 9 when not doing anything intensive at all.
    brand new spectre x360 with intel i7-1065G7/


    https://imgur.com/Es0n9le
    I've undervolted it a bit as the fan very easily turns on and the thing gets really hot so hoping optimise it a bit better to keep it cooler and quieter
     
  5. IntelUser

    IntelUser Notebook Deity

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    I think you are fine, as it has C8 active. Just see if you can lower the impact of background applications somehow so its in the lower states more often. Lower the C state the harder it'll be able to reach. What's your package power?

    Honestly for Icelake, idle power is excellent. The problem is that the process/uarch is still immature and the voltage/frequency scaling is poor. Hence when its anything above idle the battery life suffers. The leaks for Tigerlake looks much better but we'll see.

    Yea that's what I'm referring to. The iGPU is controlled by internal mechanisms and can be power gated so don't worry about that. The iGPU doesn't use the PCI Express to connect to the rest of the CPU either - its all connected using the ring bus.
     
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  6. Griffin3567

    Griffin3567 Notebook Enthusiast

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    1.2 to 1.5 W when idle.

    I just sat and watched it for a few minutes when idle and it didn't enter C8 at all.
     
  7. IntelUser

    IntelUser Notebook Deity

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    @Griffin3567 Your image is showing C8 at 16% of the time. It looks like it can go lower, but is it at least going into C7?

    Your package power should be able to reach under 0.5W. Beyond that it'll have a minor impact, but 1.2-1.5W is quite high.
     
  8. guozz1

    guozz1 Newbie

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    Che0063 thank you for the guide, previously managed to achieve 0.5w pkg power on my 9750H gigabyte aero 15, but had to reinstall everything due to an accidental wipe. I've been trying for a day, installing factory image and also a fresh copy of the latest windows, updating my drivers regardless it's Stuck in C3. Reading your C-states guide again, I uninstalled the Intel RST drivers and BINGO!
     
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  9. andriii25

    andriii25 Newbie

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    Hi, I just registered here to show my thanks for this guide, and to the results here.
    I recently bought an Acer Aspire 7 A715-73G with an Intel i7-8705G CPU. I read decent reviews about its battery life. However, it could barely do 4 hours in idle (or well, which I thought to be idle then). With a 48 Wh battery, that means 12 W in idle, I think we can all agree that's absolutely unacceptable.

    I was this close to RMAing the notebook, but I found this guide. I have to note that before trying everything here, I also tested the battery life in an Ubuntu live USB, and even that showed tremendous improvement. Previously in Windows when streaming 1080p videos it used ~18 W, and in the Ubuntu live install that decreased to ~9 W. This is without any powertop autotuning or tlp installed.

    Now when I rebooted into Windows to start the guide, for some unknown reason the power consumption was much much lower than before. I could get 2.2-2.3 W in idle on 0% brightness, 2.8-2.9 W with 30% brightness, which is absolutely amazing. With that, I could finally reproduce what various reviews showed me. After that, I did most things in the guide here.
    I undervolted the CPU by -150 mV, maybe I could go lower, but that's enough for me. Package C states are mostly (80%+) in C8, which is pretty cool.

    Now after a restart, some update got installed with Windows 10 and in idle it's 4.8 W, slightly more when browsing the web. I find that a bit weird (why did it increase?) but I'm satisfied, with this the laptop is decently portable. I still wonder why this happened after booting into Ubuntu. Maybe some drivers got updated just before that? I have no explanation really.

    I attached my ThrottleStop settings here if anyone with a similar laptop or CPU has anyone problems.
    (EDIT: Just saw that the C State windows covers it, but I also have "Disable Turbo" checked in TS. Also the temperatures are normally around 40 °C, I just ran a benchmark before the screenshot)
    [​IMG]
    [​IMG]
     
    Last edited: Jun 8, 2020
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  10. IntelUser

    IntelUser Notebook Deity

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    @andriii25 Wooot! Congratulations! Though I can't think of a reason why it would do that? Maybe Linux smacked Windows on the head and forced enabling all power saving features?

    I kid!

    Unrelated news, but Intel announced Core processor with Hybrid technology "Lakefield". It should reach new levels of low power and battery life for x86 devices.

    Modern standby should be far more effective as well with its C10 power state being rated at a mere 2.5mW. That's a 12x difference from Amberlake Y's 30mW figure.

    I'm interested in getting one if they make a device in the proper form factor. 2.2lbs 40WHr+ battery, convertible please!
     
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