memory compatibility issue with DTM64419 modules and Supermicro X9DR3-F motherboard

[mrtn]

I have a Supermicro X9DR3-F motherboard with 8x MT36JSF2G72PZ-1G9N1KF modules installed. I wanted to add another eight 16GiB modules and installed 8x DTM64419 DIMMs. However, the server did not complete POST and was stuck at "System Initializing 19" POST code. I managed to boot the server once with two DTM64419 modules added, i.e 8x MT36JSF2G72PZ-1G9N1KF and 2x DTM64419, but after the reboot the server was again stuck at "System Initializing 19" code. According to manual, the motherboard supports up to 512GiB of registered memory.
Could it be that there is indeed some compatibility issue between the DTM64419 modules and Supermicro X9DR3-F motherboard? Or between the DTM64419 and MT36JSF2G72PZ-1G9N1KF modules? Any other ideas?

 

[mrtn]

I bought two additional MT36JSF2G72PZ-1G9N1KF memory modules and installed those to P1-DIMMA2 and P2-DIMME2 slots as described in the motherboard manual:



In other words, now I had 10x MT36JSF2G72PZ-1G9N1KF modules installed. However, with ten MT36JSF2G72PZ-1G9N1KF memory modules , the server again does not complete the POST and displays the "System Initializing 19" POST code. When I remove those two added modules, then the workstation boots without issues. BIOS version is 3.3.

Any ideas, what might cause such behavior? What else to try?