High CPU usage when screen turns off

[Ineptules]

Almost imediatly after the screen turns off (not sleep mode) the fans kick in. So I suspect something is causing high CPU usage when the display is off. Is there a way to find out what it is? 

I'm on the Windows 10 Creators Update (but it happened before). HP Support Assistant says my drivers are up to date.

Thanks!

[mdklassen · Accepted solution]

> I suspect something is causing high CPU usage when the display is off. Is there a way to find out what it is? 

Windows does have "background" tasks -- tasks that run when the computer is otherwise idle, such as:

* search indexer

* disk defragmenter

* virus-scanner

* Windows Update

Before the display darkens, start the Windows "Task Manager" (CTRL-ALT-DELETE).

Switch to the 'Performance' tab.  Observe the CPU meter -- how busy the CPU is.

Don't touch the computer -- let the screen go "dark" and wait for the CPU to get "busy",

and for the motherboard react to the extra heat generated by the CPU by speeding-up the fan.

Then, "wake" the screen, and look at the CPU meter, and whether the CPU has recently been running at 100%

At the bottom of that 'Performance' tab, click 'Resource Monitor'.

Click its 'Performance Tab'.

Expand the 'CPU' section.

Again, don't touch the computer -- wait for the "darkness".

Again, wake it, and look at that 'CPU' section, for a list of processes, and what percentage of the CPU each is using.

Model-number of your computer?

Which Operating System?

How old is the computer?

[Ineptules]

It was indeed one of the background tasks. I used the "resource monitor" and found out it was something Windows Defender related, so I delayed those tasks.

Thank you very much!

[mdklassen]

>    It was indeed one of the background tasks. I used the "resource monitor" and found out it was something Windows Defender related, so I delayed those tasks.  Thank you very much!

Yes, some of those "background" tasks run at "Idle Priority" -- use the CPU only when you are not using it.

Did the high-CPU activity start just after you installed that "preview" of Windows?

It could have been Windows Defender doing a "first-time" scan, to establish a "base" reference point for the newly-installed O.S.

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