OWC 16GB DDR4 2400MHz PC4-19200 CL17 1.2V 288pin Server DIMM ECC Registered memory compatible with Lenovo System models x3550 M5 (8869) and x3650 M5 (8871). ECC REGISTERED UPGRADE: This type of memory is used in Workstations and Servers. It will NOT be compatible with standard desktop computers. Also, it cannot be mixed with UNBUFFERED memory. INDUSTRY LEADING: Consumer-friendly Advanced Replacement Program and Limited Lifetime Warranty, which includes Free Tech Support by Other World Computing. MAXIMIZE YOUR SERVER: With OWC's ECC Registered Server Memory, you will extend the life of your old infrastructure or save money when building a new one. Replacement for Lenovo part number 4X70G88330.