Sorry to hear you are having troubles. Being a PT user for so many years, I’m sure you know your way around PT, but I have to ask if you followed the set up, troubleshooting and optimization tips in the
Help Us Help You thread.
Have you tried removing your plug-ins and trying a basic session to see if stability returns? If it does, add them back one at a time until you find the one that causes instability.
There are also a bunch of threads about newer, high core count systems performing better with processor affinity tweaks.