Strange division of CPU use shown by Task Manager

When I use Handbrake to transcode video, CPU utilisation flatlines at 100%, expected for such a compute-intensive task:


However, when I look at the details tab in Task Manager, it shows the majority of CPU is being used by System Idle Process, which seems to me to make not too much sense. The CPU use by Handbrake goes up and down by a few percent, but it never shows as more than about 40%.


If I pause Handbrake, then System Idle Process goes to 98-99%, and on the performance tab, CPU utilisation drops to 1-2%. Resume Handbrake, and CPU goes to 100%, but System Idle still shows as being the majority of that. Seems to me that either the CPU utilisation on the performance tab is wrong or the System Idle Process percent of CPU on the details tab is wrong.

Have a look at the suggestions HERE .

Change the CPU chart to draw all logical processors and cores. If one core goes to 100% then the chart you use, will show 100% usage even if all the other cores has no usage. There's no chance in the world, Handbreak uses all your CPU cores 100%. That's just how transcoding works.