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 256GB UPGRADE: Consists of a single 256GB DDR4 2933 PC4-23400 CL21 8Rx4 288-pin 1.2V ECC Load Reduced DIMM Memory RAM Module Upgrade compatible with Supermicro Motherboard models X11DPD-L, X11DPD-M25, X11DPFF-SNR, X11QPL And X11SPA-T. 100% COMPLIANT: JEDEC-Standard and ROHS Compliant. Warranty-Safe Upgrade. Designed and Tested to Meet or Exceed all Manufacturer OEM Specs. 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. INDUSTRY LEADING: Consumer-friendly Advanced Replacement Program and Limited Lifetime Warranty, which includes Free Tech Support by Other World Computing.