KOMPUTERBAY 4GB FULLY BUFFERED PC2-5300 DDR2 ECC (FB-DIMM) (2 X 2GB) FOR APPLE KIT Memory ECC Fully Buffered (an FBDIMM will not fit into a standard DDR2 socket, and a standard DDR2 module will not fit into an FBDIMM socket) Capacity: 4GB For Apple Mac Pro (8-core) Desktop Speed: PC2-5300F 667MHz CL 5 Thermal Heatspreaders for Cooling 240-Pin FBDIMM Fully Buffered Lifetime Warranty