From what Ive read the drivers appear to be working markedly better. My first 390x will arrive here on Wednesday Il post to let you know how I get on as its a fresh install as well. Are all your other drivers Bios etc up to date? I just recently built a "new" system but recycled various parts from a previous build I left Asus AI suit on the SSD i loaded windows onto and it caused havoc with my MSI mobo crashing cards and stopping me from shutting down. Could it be something similar?
Just a thought, Sorry I cant be anymore help.