I've noticed a dramatic slowdown on both of my Windows 10 desktop PC's performance after upgrading from 2.x to 126.96.36.1999.1075. I did the full clean and installed the new version in both PC's, but there was no difference. Most affected by this slowdown was our Acronis backup which was taking about 20% longer and "CCleaner/Registry/Scan for Issues" which is taking about 275% longer!
So . . . I experimented a bit and have found the problem! Using "CCleaner/Registry/Scan for Issues" as my "test vehicle", I turned different parameters off and on until I located the culprit! With the "Enable self-protection module" off, Scan for Issues takes 6:43 seconds (seconds:hundredths). With the same module on, Scan for Issues takes 18:54 seconds. These times were taken with a simple stop watch, so they could all be +/- 1 second, although I ran the tests a bunch of times and got comparable results to the above times with every test! No other parameters seemed to make any difference with this testing. Note that with "Enable self-protection module" turned off, Acronis backup times returned to normal and other applications returned to their normal (fast) speeds.
So I think someone at MWB needs to take a look at the "Enable self-protection module" and find out why it crippled both of my PC's, as well as many other users I'd guess. In the meantime, I'm keeping the parameter turned OFF!
Any questions, please ask. If you'd like me to take part in any tests, I'd be glad to help.