Hello.   Load Reduced DIMMs (LRDIMMs) are not supported on this server. Yes, supported DIMM speed depends on DIMM type, DIMM voltage and DIMMs-per-channel populated. Low voltage DIMMs have lower operating frequency of up to 1333 MHz. When DIMMs of different speeds are mixed, they will operate at the speed of the DIMM with which is the lowest.    To achieve the desired memory capacity is 192 GB, use 12x 16GB memory modules such as P/N JDF1M with speed of 1600 MHz  
Hi, the server in question is a poweredge R420, E5-2430 [NAME].2Ghz Does this support 32GB LRDIMM? As in, the load-reduced quad rank dimms. According to the documentation it appears that when using two normal quad-rank RDIMM in one channel, the top operating frequency is 1066 MT/s whereas two dual-rank allows for 1300. So, if I were to buy quad-rank LRDIMMs would they behave like dual rank? Is it even worth it for performance? I am looking to bring the server up to about 192 GB or so. 
R420 RAM question