Windows 8 and 8.1 Forums


Why, when my netbook is on power save mode (CPU clocks dow

  1. #1


    Posts : 103
    Windows 8.1 64 Bit

    netbook 59% max CPU usage when on power saving mode


    Why, when my netbook is on power save mode (CPU clocks down to 0.97GHz from 1.67GHz), its CPU usage won't go past 59% when doing something intensive? Is Windows 8.1 limiting the CPU usage besides underclocking it? Is it measuring the CPU usage with respect to a full clocked CPU? Am I missing something? Windows XP shows 100%.
    Any clue will be appreciated.
    Last edited by derek10; 14 Aug 2014 at 10:48.

      My System SpecsSystem Spec

  2. #2


    Posts : 22,568
    64-bit Windows 10


    Hello Derek,

    Double check to see what your min/max processor state is set to in your power options. I like to keep mine set like below.

    Power Plan Settings - Change in Windows 8

    Click image for larger version

    Hope this helps,
    Shawn
      My System SpecsSystem Spec

  3. #3


    its called processor Scaling, and its done for powersaving and thermal considerations. its performed by reducing the clock multiplier on the CPU, and thus reducing its overall frequency (GHz). most processors are 100-166Mhz but the clock rate allows it to perform multiple operations per cycle. Some will tell you that it is more harmful to the hardware than it is good. Put your power option to high performance and a shortcut on your start page for sleep...
      My System SpecsSystem Spec

  4. #4


    Posts : 103
    Windows 8.1 64 Bit


    Thanks to both

    I have it configured on 5% on max and min in Power save and I use balanced when more power is needed or it's plugged in, the netbook works fairly well on this mode as I use it for basic things as word processing and Internet browsing while saving battery.

    But my problem is that in this setup the CPU usage is up to 59% and I don't know if Windows 8 is limiting the usage or it's a new way to measure CPU usage, In XP and previously with 7 I get 100% with this same settings (in XP with Samsung drivers and utilities).

    Click image for larger version
    Notice the spike, it's because I've changed to Balance and back to power save mode.
    Last edited by derek10; 14 Aug 2014 at 13:56.
      My System SpecsSystem Spec

  5. #5


    Posts : 22,568
    64-bit Windows 10


    Derek,

    Yep, the 59% is just what is currently being used. It's not for what is able to be used.

    A good setting in your power options is 5% MIN and 100% MAX like in my screenshot. This way Windows will be able to use up to 100% of your CPU if needed.
      My System SpecsSystem Spec

  6. #6


    Posts : 103
    Windows 8.1 64 Bit


    Quote Originally Posted by Brink View Post
    Derek,

    Yep, the 59% is just what is currently being used. It's not for what is able to be used.

    A good setting in your power options is 5% MIN and 100% MAX like in my screenshot. This way Windows will be able to use up to 100% of your CPU if needed.
    Many thanks again Brink, but why does XP show 100% CPU usage under the same circumstances?

    Click image for larger version

    I know your setting is the optimal one in most cases, but I have to use the netbook for long times on battery and I have to do this to get it, as it's old (+3 years) and its battery is somewhat degraded.

    My doubt is if Windows 8 is limiting CPU usage besides underclocking (thus reducing performance even more) it or is a new way to measure usage based on its maximum clock? I would try running a benchmark like Passmark comparing both but it would heat my netbook a lot and would took plenty of time.
      My System SpecsSystem Spec

  7. #7


    Posts : 22,568
    64-bit Windows 10


    If you have your MAX % set low in power options, then that would limit the CPU usage.

    Windows will also automatically reduce CPU usage if it detects that the CPU is overheating.
      My System SpecsSystem Spec

  8. #8


    Posts : 103
    Windows 8.1 64 Bit


    So Windows 8 is limiting the CPU usage besides underclocking the CPU while XP doesn't. It works fairly well for a netbook underclocked to 1GHz and 59% max CPU usage. Good job MS optimizing Windows 8 on slower hardware.
    Many thanks for your help and patience.
      My System SpecsSystem Spec

  9. #9


    Posts : 22,568
    64-bit Windows 10


    Glad we could help.

    Yep, depending on what you set for min/max in power options, it will have Windows scale up and down the processor based on demand. It's all designed to help save battery life, energy, and reduce heat when the CPU doesn't need to be run at 100%.
      My System SpecsSystem Spec

Why, when my netbook is on power save mode (CPU clocks dow
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