Are you using, or attempting to use, any over-clocking tool?
What version of Windows 10? 1909?
Any performance settings?
Are you a laptop? If so, what is the state of your battery?
Thanks for the fast reply!
No overclocking tool used or attempted. Just spontaneously changed a couple days ago.
Windows 10 Pro, 1909, OS build 18363.592.
Not sure what you mean by "Any performance setings?". BIOS settings are pretty much stone standard as shipped.
Yes, it is a Dell Vostro 15 3558, 8GB RAM, 500GB SSD. Battery is 92%, battery health says good and it is running on AC.
Well, good news. I guess the computer decided it had enough of the slow running and is now back to full speed.
I was getting ready to swap HDs and put the one with my Windows 7 installation in to see if it was related to Windows 10. I shut the computer down and started it up again to check the BIOS. When it started up it complained that it couldn't recognize the power supply and then offered to run a diagnostic. I ran it and it found nothing so I rebooted it again. When it started up into Windows 10 everything was back to full speed and the battery charged to 100%. Of course, I had already rebooted several times which had changed nothing.
The only thing I can think of is that it was unhappy with the power supply for some reason and slowed things down. We did lose power for a few minutes the other day which may have been when the problem started.
At least it is running right now and I can go back to normal use of the computer.