16 GB (4X4 GB) DDR2 800 MHz ECC FB DIMM Apple Mac Pro 3.2G
Apple never used DDR2 667 DIMMs in your Mac Pro model, to keep running your Mac Pro at optimal speed always use DDR2 800 DIMMs. Use of DDR2 667 VS DDR2 800. Thin heat sinks. 72 Bit ECC Fully Buffered DIMMs.