For those wondering what this NVidia driver problem is all about, here is a link to the relevant discussion:
TL;DR: in VR only, every drivers since 451.48 (reported) or at least since 446.14* are causing frame drops and stutters in any VR games. I’m not sure this is SteamVR related only or broader.
*this was the last driver pre-Win10 2004 before introducing Hardware Assisted GPU Scheduling - aka HAGS
[05DEC2020 update]
A couple days ago there was a HP Reverb AMA on Reddit with the following news about this NVidia driver bug: