I’ve had some long-standing issues with memory in my servers and have now realized that according to AMD, EPYC only supports quad-rank LRDIMMS (not dual-rank), though it supports dual and single rank RDIMMs. I had assumed that if something supports dual rank DIMMs it supports dual rank DIMMs, no further research necessary - clearly I was wrong.
That said, the behavior I get is really unusual with dual-rank LRDIMMs: Channel A and H get disabled, and channels B,C,D,E,F,G all work fine, no matter how I rearrange my 8 sticks. This goes for all 3 processors and motherboards I’ve tried (2 7302 CPUs and a 7252, on an EPYCD8-2T and a ROMED8-2T motherboard)
Before I go buying another 8 sticks of RDIMMs, I’m hoping to hear if you folks have experienced similar issues