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 64GB UPGRADE: Consists of a single 64GB DDR4 2933 PC4-23400 CL21 4Rx4 288-pin 1.2V ECC Load Reduced DIMM Memory RAM Module Upgrade compatible with Fujitsu PRIMERGY models CX2550 M5, CX2560 M5, RX2530 M5, RX2540 M5 And RX4770 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 Fujitsu part numbers S26361F4083E464, S26361-F4083-E464 , S26361F4083E964, S26361-F4083-L464, S26361F4083L464 and S26361F4083L964.