BL460c Gen9 won't boot with E5-2699v3 processors and 384GB of RAM

[serverscott]

I am upgrading the memory in my BL460c Gen9 blade with two E5-2699v3 processors installed.  Because of these processors, the server has the wider heat sinks installed, which block the use of DIMM slots 4&5 (so only 12x DIMM slots available).  I need to get to 384GB of RAM in this server, so I am using 12x 32GB 4Rx4 LR PC4-17000 DIMMs (DDR4).  When I try to boot with all of the available DIMM slots populated, the server hangs on the boot-up.  Since this configuration breaks the normal DIMM population rules, is there a setting I need to change in order to get this to work?  It says that 384GB of RAM is supported in this server with the wider heatsinks installed, but I just can't seem to get it to work.

Any information is greatly appreciated.