Win 10 20H2 problems with Z220 SFF

[sejarzo]

I noted a lot of pops and clicks developing in audio playback after allowing Windows Update to install the 20H2 update on an Z220 SFF that had run version 2004 flawlessly. For some reason, those didn't evidence themselves until I was just beyond the rollback period.

Over the past few days, I noted high cpu usage (45-55%) for System/Diagnostic Policy Service/Diagnostic System Host. I completed the typical recommended steps to fix that--stopped the services, deleted srudb.dat, ran sfc/ scannowwhich claimed to have fixed corrupted files)--but every time I restarted Win10, the same problem started.

I had created a USB installation USB stick with 20H2 from the MS official site and decided to bite the bullet, wipe out my SSD, and reinstall 20H2.

I did nothing more than install it and complete the registration and configuration steps. When I got to my desktop after the final restart in that process, I had EXACTLY the same problem with high CPU for System/Diagnostic Policy Service/Diagnostic Service Host with no other apps loaded, no updated drivers, nothing--just the "pristine" install of 20H2. Nothing changed after letting it sit for 25 minutes.

Luckily, I still had a USB stick for ver 2004, so again, I wiped out my SSD and reinstalled it. No problems at all now.

I never had major CPU usage issues with Win10 on this machine ever since I obtained it off-lease in 2018 and installed ver 1803 and all version updates since that time.

Because the same problem occurred after allowing Windows Update to upgrade from 2004 to 20H2, and with a freshly generated USB stick with 20H2 on a clean SSD (removed, attached to another PC, diskpart used to remove all 4 partitions) it appears to me that there is some inherent problem with 20H2 on this particular computer.

Has anybody else noted similar issues?