647658-081-PCW is a HP Compatible 8GB PC3-10600 DDR3-1333 2Rx8 1.35v ECC UDIMM (generic for HP PN# 647658-081). This is a 'major brand' module kit (from either Samsung, Micron, Hynix, Infineon, etc.), equivalent in every way to HP original memory. All PCW modules meet or exceed OEM specifications and JEDEC standards.