48 GB DDR3 ECC Registered Kit (PC3-1333, DDR3-1333MHz)- (6x8GB) For Dell Precision Workstation T5500, T7500. Dell P/N A2626071, A2626092, A3721494, A3721500, A3721505. Major brand DIMMs manufactured by Hynix, Micron & Samsung Buy with confidence each DIMM is tested in Dell servers for 24 hours Lifetime warranty ECC Registered DIMMs & ECC UDIMMs can not be mixed. If your system came with ECC UDIMMs then use of registered DIMMs will require removal of all exisiting UDIMMs. Operational memory speed is controlled by CPU type and number of DIMMs installed. eFetcher's mission is to provide its customers a variety of computer products and excellent service at affordable prices. We have been selling computer parts to consumer since 1989 and we have over 500,000 satisfied customers. Buy with confidence, we test upgrades overnight and pack every order professionally to meet and exceed your expectations. Over 24 years in business Over 500,000 satisfied customers Lifetime warranty on memory upgrades 100% compatibilty is guaranteed 30 days money back guarantee .