I have an r740xd (well vxrail p570f, same difference) I have some random micron 16gb rdimms (2666 and 3200 variants) I am running currently. I am trying to upgrade to 32gb rdimms. I buy a mixed lot of hynix/samsung 32gb pc4-3200aa rdimms on ebay. None of the new 32gb rdimms are recognized by my r740xd. I have never had an incompatibility where a server would not even recognize a rdimm in several different systems/manufacturers with many different rdimms over the years. Now I have 11 rdimms that won't recognize in my server. I don't have another system that will take ddr4 rdimms so I am not sure is this something wrong with Dell or could this guy have really sent me this many bad rdimms? I tried just running them 1 at a time in slot 1 and not one is utilized but if I put my old ram back it boots right up.