I just noticed that Interface was filling my 16GB of RAM within about 5 seconds of arriving in a domain.
So I tried turning off Dynamic Texture Management, and everything seems normal now - RAM usage is only two or three gigs and it’s not cutting back to the default Vive screen all the time like it used to.
I tested with & without the option again at the Earth spawn point - the problem and the workaround were repeatable.
If you’d like any other info please let me know. I’m on 5429 on Windows with an AMD 290 and a Vive.