Sorry for the late reply, but I figured out and cured my overheating problem. It was the Vega itself. I upgraded my system to the i7-9700k listed to the left. I installed a water cooling loop and cured my temp issues, but I still had crashing issues. Then I realized it was crashing to power off, not a lockup. I posted a thread on Tom's Hardware and I got JonnyGuru (The Power Supply reviewer) himself responding to me, and saying his many Vega tests all report very poor power regulation in the Vega 64s and they were getting huge micro power spikes of twice the normal power draw.
He said the recommended 650 wat PSU was never enough. The micro spikes would trigger a power fail and shut off the PSU. He recommended a quality 700 watt unit, I seen a same unit, but 750 watts that was $10 more, so I thought I'd hedge my bet and pay the extra $10 for the 750 unit.
Since I installed it, I have had zero issues whatsoever,
I should have realized this from my old radeon 1800XTX that had the same issue. Some one it was the PSU causing the crash. I ignored him as I had recommend and it was a quality one.
Then I built another rig, with a x2 video card and needed an even bigger PSU, so I tested that PSU on the 1800XTX system and all troubles disappeared.
You'd think I'd have learned my lesson, apparently you can't teach this old dog new tricks. lol
FYI, I looked it up, I replaced it with a Seasonic PRIME PX-750, 750W 80+ Platinum, and I ordered it on 9/10/2019.
So, it has been a while since I replaced it, and the Vega is still holding it's own and trouble free.
