4GB Kit (2x2GB) DDR2 Fully Buffered PC2-6400 800MHz (DDR2-800) FB-DIMM Memory for 2008 Apple Mac Pro (Apple P/N MB193G/A) 240Pin DDR2 Fully Buffered Dual In-line Memory Module (FB-DIMM) 4GB Kit (2pcs of 2GB) PC2-6400 / 800MHz, CL5 72-bit wide, Error Correcting Code (ECC) Genuine Samsung or Micron board/memory chips