This is a Kingston Server Premier registered DIMM built for server and workstation motherboards that support DDR5 ECC RDIMM memory. It offers 64GB of capacity per module, running at 6400MT/s with CL52 timings in a dual-rank (2Rx4) configuration, and uses SK Hynix 'A' DRAM chips. ECC (error-correcting code) support automatically detects and corrects memory errors, which matters for servers and workstations running long uptimes, databases, or mission-critical workloads where silent data corruption isn't acceptable. Registered (buffered) DIMMs like this one reduce electrical load on the memory controller, letting a server populate more DIMM slots reliably. Typically bought in matched sets to fill a server's memory channels for maximum bandwidth.