Windows 10 - One CPU running at 100% after return from display being turned off

[GriffMG]

Has anyone else had this, I think it is quite a recent thing (on my machine).

Normally, when idle, my laptop runs at 1-2% capacity on the CPUs. If I leave the machine alone for a bit and it turns the display off (after five minutes)
when I return the first CPU is running at 80-90% in taskmgr. The processes screen in taskmgr does not show any thing that comes close to that utilisation.

I narrowed it down to the 'display off' by making it 'never' this morning - and the high usage has not returned.

Malware reports nothing awry, nor does sfc or dism.


Any ideas gratefully received

Regards

Griff
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[xwb]

Do you have any background tasks that "run when machine is idle"?

It could be system update - does the CPU go high if there is no internet connection?

 

[GriffMG]

System update is disabled, no background tasks.

I've not let the system turn the screen of for two days now, and the high usage has not recurred.

When it was running that first core at 80-90% I couldn't find anything running in the background.

This is Windows 10 Home BTW and fully up to date.

Regards

Griff
Keep [Smile]ing

There are 10 kinds of people in the world, those who understand binary and those who don't.

I'm trying to cut down on the use of shrieks (exclamation marks), I'm told they are !good for you. ​

 

[xwb]

It could be windows defender or a self defragmentation.

 

[GriffMG]

Maybe defender, but there is no hard drive activity so a defrag is out

Regards

Griff
Keep [Smile]ing

There are 10 kinds of people in the world, those who understand binary and those who don't.

I'm trying to cut down on the use of shrieks (exclamation marks), I'm told they are !good for you. ​