After 1 month at 4.2Ghz, it attempted the 1st stabilization of a 4k video & prompty crashed. It wouldn't post anymore until the clockspeed was lowered to 4.1Ghz & memory was lowered to 3400Mhz. The voltages remaned on auto. No manual voltage tweeking improved it.
It was the end of an era. There probably is a short term fuse which lasts just long enough for product reviewers to hit a higher threshold & throw it away. Like an old fashioned lightbulb, it eventually burns out.