Recently (as of last night actually), I had updated the drivers for my FocusRite interface. Crackling, poor performance, etc. is what entailed. It took me a little bit to figure out what was going on (never mind that I was imbibing ?.
Anyway, I wound up uninstalling everything focusrite including registry items, and pulled out the initial CD from 2013 and installed it from there.
PFM! Everything returned to 'normal' as in low latency, VST instruments responding and the like and well, more like one would expect.
FWIW, I've had the same thing occur in my work environment for 'new' video drivers being installed. Worked great for about 10% of the users (2500 users), though the rest suffered. Sometimes it pays to keep old installers.
Working in software engineering, sometimes you just don't want to fix something that isn't broke. Always keep a working backup.
Yes Really! BACKUP ?