256GB Kit ( 4x 64GB Modules ) DDR4 2666 MHz ( PC4-21300 / PC4-2666V-R ) DDR4 DIMM ( 288-Pin ) ECC RDIMM ( Registered DIMM ) 2S2Rx4 ( 4Rx4 Quad Rank x4 3DS/TSV ) 1.2V - DDR4 Standard Voltage Compatible with DDR4 SERVERS and WORKSTATIONS only *NOT compatible with desktop or laptop computers* Please verify the supported memory (RAM) specifications of your system prior to purchase to ensure compatibility Boosts the performance of your server or workstation by speeding up loading times, improving system responsiveness, and increasing your system's ability to handle greater workloads All modules undergo quality assurance testing to ensure dependable and reliable performance Please refer to your system's manual for proper memory seating and channel guidelines A-Tech provides a Lifetime Warranty for all orders & offers complimentary United States based Tech Support before, during, & after your purchase