Increase installed memory capacity in compatible Cisco UCS servers with a 256 GB DDR5-6400 ECC registered DIMM. This Axiom Memory module uses a 4Rx4 organization and targets server platforms built for high-density DDR5 RDIMM populations. ECC memory supports error detection and correction capabilities when used with a compatible server memory controller, while the registered DIMM format is intended for enterprise server memory channels rather than desktop DIMM slots. DDR5-6400 identifies the module’s 6,400 MT/s speed grade. Validate the server generation, processor memory-controller support, installed DIMM population, and platform firmware requirements before deployment. A 256 GB module can reduce the number of occupied memory slots required to reach a target capacity, which can be relevant where a server configuration needs substantial memory per socket or room for future expansion. UCS-MR256G4RG5-AX is the Axiom Memory ordering code for this Cisco-compatible 256 GB ECC RDIMM. The combination of DDR5-6400 operation, registered buffering, ECC capability, and 4Rx4 organization distinguishes it from lower-density or unbuffered memory options. Select it only for systems that explicitly support 256 GB DDR5 ECC RDIMMs at the required operating speed; actual memory speed and usable capacity depend on the host platform’s supported configuration.