So I just recently purchased a refurbed Mac Pro 2008 and it came with 2 4GB 667Mhz DDR2 FB-DIMM memory modules. These modules are covered on both sides with a metal sheet so I don't know if that's right? This machine is replacing my 2006 1.1 that stopped booting fully some months ago. From what I know the 2008 3.1 Macs used 800Mhz DDR2 240 Pin Fully-Buffered DIMM modules. Can this 2008 use 667 modules safely? If so can I pull the rest of the matched pair 667 modules from the old 1.1 and use them in the 2008? I guess the slot config is the same?