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 32GB UPGRADE: Consists of 4pcs of 8GB DDR3L 1600 PC3L-12800 CL11 1Rx4 240-pin 1.35V ECC Registered DIMM Memory RAM Module Upgrade compatible with Lenovo System models x3650 M4, x3650 M4 BD, x3650 M4 HD, x3750 M4 And x3755 M3. 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 numbers 00D5035, 00D5036, 46W0700 and 46W0771.