high CPU usage with Windows 10 on another HP Compaq Pro 6300 MT

[MRFSYS]

We're having the same problem that we solved on another HP Compaq Pro 6300.

3 system processes in Task Manager are using a minimum of 40% of  the CPU during idle.

I've scoured the Internet for solutions, but it seems there is no readily available fix,

even after we use the same settings that worked on our other HP Compaq Pro 6300.

[MRFSYS]

p.s. I can't get the screen shot to display here. 

Is a certain image format required e.g. .gif or .jpg or other?

PLEASE ADVISE.

[MRFSYS]

I can see the image file in the composition window,

but the uploaded image file does NOT show after I do a "Post".

Again, is a certain image format required e.g. .jpg or .gif ???

[MRFSYS]

URL with .gif

[sejarzo]

Sounds like the same issue I had with my Z220 SFF when I initially allowed Windows Update to upgrade to 20H2 from 2004. Unfortunately it didn't seem to happen right away and when I realized it, I was beyond the simple rollback period.

I eventually wiped my SSD and reinstalled Win10 Pro 20H2 from a USB installation stick generated on November 12, and as soon as the installation and configuration restarts were complete and I reached my desktop, I had that problem. 40-45% CPU used by System, Service Host: Diagnostic Policy Service, and Service Host: Diagnostic Policy Host (I think.)

I had to wipe the SSD again and reinstall Win10 Pro 2004. Everything is fine now.

My 400G1 Mini also had problems with 20H2. Unsure re CPU usage but I could not use it to listen to any audio via a DAC attached to any USB ports. Constant pops/ticks/dropouts that resolved when I reinstalled 2004.

[MRFSYS]

Many thanks for those useful details: 

when you reverted to an older set of system software,

the problem disappeared.   Correct??

That says to me that the source of the problem is somewhere inside Microsoft OS code.

Here's what I wrote this morning to a third-party utility software vendor

located in another country:

One theory  I am testing is the Ethernet option

of ENABLING/DISABLING "Wake On Magic Packet".

That sounds to me as if a hacker can penetrate my

cable modem, router and switch, to STARTUP my PC

and plant a hidden virus somewhere in my copy

of Windows 10 AS LONG AS "Wake On Magic Packet"

is ENABLED.

I have DISABLED it now, but it may already be too late ...

Because I have located numerous similar complaints

and help requests, by searching the Internet,

this may be an illegal attempt to force

extra CPU usage and to cause extra power

consumption, without most end users

even knowing this is happening.

Or, to conduct secret surveillance of this HP workstation.

Thinking back, I do remember 2 recent events that

were abnormal:

(1)  the USB cable to our APC battery backup unit

failed, and the Power Chute software flagged an error

something like:  "cannot connect to battery backup unit";

(2)  at the same time (almost same day), the audio jack

on the rear of this HP workstation suddenly stopped working,

so I moved the audio cable to the front headphone jack

and now my speakers are working properly again.

If these peripheral ports were experiencing hardware failure,

it's unlikely that they would resume working perfectly

a few days later, and continue working perfectly

without any more of the same or similar symptoms!