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 memory. OWC 64GB DDR4 2666 PC4-21300 CL19 4Rx4 288-pin 1.2V ECC Load Reduced DIMM Memory RAM Module Upgrade memory RAM module, with the exact same specifications as QNAP part number RAM-64GDR4ECS0-LR-2666. 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.