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. OWC 64GB UPGRADE: Consists of 4pcs of 16GB DDR3L 1600 PC3L-12800 CL11 2Rx4 240-pin 1.35V ECC Registered DIMM Memory RAM Module Upgrade Kit memory compatible with Supermicro Motherboard models X9DRFF Series, X9DRFR Series, X9DRG Series, X9DRH Series And X9DRi Series. 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.