Ah for sure I could do with more RAM. However I don’t believe that is the issue in this case, as there has been a massive drop in performance over the space of a week. I can now no longer playback 1080p pro-res 422 footage in Premiere – whereas I still have no trouble with playback and editing of up to 8K footage in Resolve or After Effects.
I first tried to update via CC manager, then did a full un-install then re-install of Premiere.