OWC 256GB (4x64GB) DDR5 4800 CL40 ECC Registered RDIMM memory upgrade

Server ECC RDIMM kit

This OWC kit supplies 256 GB of DDR5 ECC Registered memory as four 64 GB modules. It is built for Cisco UCS C220 M7 SFF, C240 M7 SFF, X210c M7 and X410c M7 servers that require registered DIMMs with error correction. Workstations or desktops that accept only unbuffered or load-reduced modules cannot use this kit.

Installation notes

Each module is a standard 288-pin DDR5 RDIMM that seats in the server DIMM slots without tools. The registered buffer adds a clock cycle, so the system BIOS must support registered ECC memory; mixing with unbuffered or load-reduced DIMMs will prevent boot. No heat spreader is fitted, so airflow across the modules must be maintained by the server chassis fans.

DDR5 4800 interface limits

The modules run at DDR5 4800 (PC5-38400) with CL40 latency at 1.1 V, matching the JEDEC base specification for this speed grade. Bandwidth and latency are fixed by that standard; higher data rates or tighter timings are not supported by these parts. Capacity scaling beyond the four modules provided depends on the memory controller and slot count of the specific Cisco UCS model.