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I have 64-bit Windows 8.1 Pro, Lenovo X220. All updates are installed (both Windows and from Lenovo Solution Center).

Every time my computer starts, one of the processes uses 25% of CPU (until computer is restarted). Task manager says it is "NT Kernel & System".

I did not find anything useful when googling (except "update windows, update drivers"). For a while I thought I can use kernview and Process Explorer - unfortunately, Kernrate Viewer is not available for Windows 8 as far as I can see.

Windows installation is quite new, antivirus updated (Syamantec), no malware detected (AdwCleaner, MalwareBytes)

How do I find what is starting this process and why it has such high CPU usage?

1 Answer 1

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Here is what I did:

  • download Process Explorer
  • show properties of NT Kernel & System and go to Threads tab
  • locate high CPU thread (in my case it was risdx64.sys)
  • show DLL view in Process Explorer and locate risdx64.sys - it is RICOH PCIe SDXC/MMC Controller Driver
  • uninstall driver

Now, card reader is not working, but CPU usage is OK.

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  • Nicely diagnosed. :)
    – Karan
    Jun 15, 2015 at 8:10
  • You saved my butt !! Display driver was doing the same in my PC, and I discovered that by the steps you mentioned. Thanks a lot.
    – Nour
    Mar 10, 2016 at 20:44

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