High CPU - NT Kernel & System, Windows 8.1 Pro 64-bit

Question

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?

Solution

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.

Comments

[Karan]

Nicely diagnosed. :)

[Nour]

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.