Saltgrass,
Going to the basis:
- I run MemTest86 individually on every single one of my Four 4GB sticks - Found that one was reporting thousands of error.
- Using one of those good known working sticks I tested every memory slot. I am not too confident with one of the banks, so I installed the sticks of the other three.
- Boot PC and tested quick opening some apps (Task manager, Chrome, Perfmon) with no issue but again,
Firefox takes close to 3 minutes to open and hug all resources during all that time (see Picture)
I am going to do another fresh install with the updated Win10 1909 USB knowing the memory is not the problem.
Probably memory was the culprit of the 1083 > 1903 upgrade failure and not creating DUMPS.