AddOn 4GB DDR3 SDRAM Memory Module - 4 GB (1 x 4GB) - DDR3-1333/PC3-10666 DDR3 SDRAM - 1333 MHz - 1.35 V - ECC - Registered - 240-pin - DIMM - Lifetime Warranty

IBM® 49Y1424 Compatible Factory Original 4GB DDR3-1333MHz Registered ECC Single Rank x4 1.35V 240-pin RDIMM