Root cause for high CPU usage; which measurement to trust more: Windows Task Manager or Process Explorer?

Consider this Windows 8.1 machine (in-place upgrade from Windows 8) with differing reports on its CPU usage. The machine is idle, and has been for 3 days. There are no CPU intensive tasks running currently nor over the 3 day idle period.

Windows Task Manager is reporting CPU usage constantly at an incredibly high value (and increasing over time!) at around 75%.

Process Explorer from SysInternals reports that the CPU usage is much different at around 42%

• How does Process Explorer report 42.14% usage, but its columns report Idle at 57%, with the sum of the other processes not even approaching 10%?

• Which of these two values should I trust more, and why should it be trusted over the other measurement?

• How can I actually determine which process is causing Task Manager to report its values?

These Proc Exp metrics were taken with Administrator privileges, and with option 'Show Details for All Processes'

Click for larger view:

Solution 1:

I looked at the picture again and see that the sdclt.exe is highlighted in green. This means the process is started. I look at many xperf traces which also show this symptoms.

The solution to reduce the CPU usage is to stop the ConfigNotification task in the Windows Task Scheduler:

Task Scheduler - Microsoft - Windows - WindowsBackup

Please, also contact Microsoft support and open a support case. They need a case to produce a fix for the backup task.