Intermittent bugs can be so
difficult. My buddy RedAnt calls them Gremlins, after the term coined by World
War II airmen. They don't reproduce on demand, so it can be difficult to know if things are fixed as
you troubleshoot and test solutions. That said, I'm entirely convinced the
crashing issue I was encountering was solved, simply by swapping my two RAM
sticks as I described. My rig passed an extended memory benchmark and I've had a
few lengthy sessions in Diablo IV
and it seems obvious that this issue is
behind me. The only problem I was having other than crashes were these
occasional odd USB resets. I suspect those are cleared up as well, but they were
even more intermittent, so I won't have the same level of confidence I'm past
them for a while longer. Thanks to those who offered tips along the way, and
hats off to those who called this as a RAM issue from the start.
Thanks Ant and Neutronbeam.