Registering only to express my gratitude to OP.
Had an old Lenovo (I guess from 2014/-15) I figured would be useful for my daughter when getting classes from home in these quarantine times. It was running win 8.1 but hopelessly bogged down with all kinds of haphazard apps (my wife had been using it for school / work but finally "tossed it" for a newer HP model).
SO, I decided to clean it up and do the upgrade to Windows 10 (i don't like the 8 / 8.1, I guess that is fair to say in this forum ^^).
Anyway, it was working fine in 8.1, after I had uninstalled all the crap and done the usual "dad fixing pc and feels like a pro" stuff. Upgraded to win10 - and was disappointed to see that it didn't quite cope?! Seemed to freeze every few seconds, much like in the old days when trying a new game on your old machine and realizing it weren't up for it.
Not the complete freeze and crash - just the annoying lag of the cursor (and everything else).
Strange, since both the CPU & Ram were about double the minimum requirements, and I wasn't running any apps or anything, I had thought it would be fine for the simple stuff, so figured it was all the windows update going on in the background.
Alas, I still had the annoying problem after all that was over. Working in a way, but exceedingly annoying.
I had made sure all the drivers were up to date before installing win 10 so I didn't even think of that being the issue... Doing the driver update on the AMD radeon did the trick (actually only had to do the usual automatic update, and it was rolled back to 2015 version through the standard "update driver" routine in devmng.
Thank you OP, surely you saved me countless hours of fruitless mocking about with regedits and malware checks (I am sure that was where i was heading eventually if I hadn't come across your post
)
Thank you, thank you, thank you!