ECC LOAD REDUCED 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 -or- ECC REGISTERED memory. OWC 512GB UPGRADE: Consists of 4pcs of 128GB DDR4 2933 PC4-23400 CL21 4Rx4 288-pin 1.2V ECC Load Reduced DIMM Memory RAM Module Upgrade compatible with Cisco models HX220c M5, HX240c M5, HXAF220c M5, HX-E-220M5SX And C480 ML M5. 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 Load-Reduced Server Memory, you will extend the life of your old infrastructure or save money when building a new one. Replacement for Cisco part number UCSML128G4RTH.