So far so good. We had a crash/reboot this morning as I had hoped.

Situation so far:

Ran the machine with only DIMM#1 in memory slot #1 for a few days with no issues. Did a few manual reboots and memtests with no errors reported.

Switched over to running with DIMM#2 in slot #2 for a couple of days. At some point last night the system rebooted itself which then loaded memtest which I had left in the optical drive (on purpose). 25 errors tested within the first pass, then the errors stopped happening. It was at 26 passes by the time I checked the system this AM. I suppose I could have checked the memtest "uptime" to tell when the system rebooted.

Now I'm on to the third test where I've swapped DIMM#2 into slot #1 - this will hopefully let me know if it's a memory module or memory controller/mobo issue.