Windows 8 using all CPU while idle RRS feed

  • Question

  • Fresh install of Windows 8. When the computer is left idle for about 5 minutes, "System" (ntoskrnl.exe) and "Windows host process (Rundll32)" will consume nearly 100% of the CPU. If the mouse is moved then the CPU usage instantly goes away, and the "Windows host process (Rundll32)" instantly removes itself from the Processes list.

    This is extremely annoying as it causes my fan to become very loud while trying to listen to music.


    Setup: Desktop, Windows 8 Pro 32-bit, Pentium D CPU, 4GB ram, 128GB SSD for OS, 500GB HDD for data, Nvidia 8800GT GPU

    I would like to disable these services so my computer does not have high CPU usage while idle.

    Any help is appreciated. Thank you.

    Thursday, April 18, 2013 8:11 PM


All replies

  • Windows runs a maintenance task when the PC is idle (defrag, optimizing .net files with ngen) and this can use some CPU resources.


    You can disable it by disabling the task in taskscheduler:


    "A programmer is just a tool which converts caffeine into code"

    • Marked as answer by Niki Han Wednesday, May 8, 2013 9:10 AM
    Friday, April 19, 2013 5:25 AM
  • Thanks for the quick answer. Unfortunately when I went to change the option, that task was already disabled. The good (or bad) news is I was unable to reliably replicate the problem. I will see if it occurs again over the next few days.
    Sunday, April 21, 2013 5:52 AM
  • Exact same issue happens to me all the time. Microsoft really needs to fix this feature as it's very inconvenient for laptop users who have loud fans.
    Sunday, July 21, 2013 7:14 PM
  • have you disabled the task?

    Also you can use Speedfan to make the fan silent.


    "A programmer is just a tool which converts caffeine into code"

    Sunday, July 21, 2013 7:49 PM