OWC 64GB (4x16GB) DDR4 2933 CL21 ECC Registered RDIMM memory upgrade

Cisco UCS ECC Registered DDR4 Upgrade

This 64GB kit provides four 16GB DDR4 2933 RDIMM modules built for Cisco UCS B200 M5, B480 M5, C220 M5, C240 M5 and C480 M5 servers. It uses registered ECC technology that detects and corrects single-bit errors to protect data integrity in critical workloads. The modules operate at 1.2V with CL21 latency and a 1Rx4 organisation. They are not compatible with standard desktop computers or unbuffered and load-reduced memory types.

DDR4 2933 Registered DIMM Constraints

The RDIMM form factor and registered buffer add one clock cycle of latency compared with unbuffered DIMMs, a design trade-off that enables higher capacities per channel on supported server platforms. Speed steps down automatically to 2666, 2400 or 2133 MT/s when the memory controller requires it. Mixing these modules with unbuffered or load-reduced ECC DIMMs is not supported and will prevent the system from posting.

64GB Capacity for Virtualisation Density

Four ranks across four DIMM slots deliver 64GB of addressable memory, a practical ceiling for many dual-socket Cisco UCS M5 configurations that populate eight slots per processor. The kit comfortably hosts multiple virtual machines, container clusters or in-memory databases within that footprint. Workloads that scale beyond 64GB per CPU will require higher-density modules or additional memory channels not addressed by this upgrade.