The used Dell 29GM8 64GB 4DRX4 PC4-2400T DIMM Server Memory Module is a Load-Reduced DIMM (LRDIMM), an LRDIMM is similar to a registered DIMM (RDIMM) in that it buffers electrical load on the memory controller. However, instead of plugging directly into the parallel memory bus that is connected to the memory controllers processors, the LRDIMM can navigate outside of these restrictions through the use of the Memory Buffer chips. When a server is exclusively configured with LRDIMMs, the memory controllers in the processors automatically shift to Serial Mode - all data, command, and control signals become packetized and transmitted to the Memory Buffer on the LRDIMMs. The Memory Buffer then handles all the Reads and Writes to the DRAM chips.LRDIMMs greatly reduce the electrical loading of the DRAM chips onto the memory bus, and through a process called "Rank Multiplication," transform a Quad Rank LRDIMM into a Dual Rank memory module for the memory controller. Through the reduction of the electrical Ranks of the LRDIMM, the server is then able to support LRDIMMs at higher speeds than RDIMMs, and with fewer restrictions on sockets. This means using LRDIMMs you can configure systems with the largest possible memory footprints. If large quantities of RAM are your goal, then using a system full of LRDIMMs RAM can help you achieve twice the capacity for your PowerEdge server.
Substitute PN:
 805358-B21-OEM
 A8711890 
 HMAA8GL7AMR4N-UH 
 HMAA8GL7MMR4N-UH
 M386A8K40BM1-CRC
 W1VVX
Compatible With:
PowerEdge R630
 PowerEdge R730
 PowerEdge R730xd
 PowerEdge T630
 PowerEdge M630
 PowerEdge C4130
 PowerEdge Fc430
 PowerEdge R930
 PowerEdge Fc630
 PowerEdge Fc830
 PowerEdge M830
 PowerEdge R630xl
 PowerEdge R730xl
 PowerEdge R730xd Xl
 PowerEdge R830