Sorry, but I am still confused and want to make sure I buy the correct Ram, can you help? I just bought a Mac Pro two 2.8 quad core, is this the way to go? "Put each pair in the AB slots top and bottom ram cards plus the pair of 1GB sticks that came with it in CD of the top ram card" So that's: 4.0GB Mac Pro Memory Matched Pair (2GB x 2) PC6400 DDR2 ECC 800MHz 240Pin FB-DIMM Modules .....right? I cant afford much more than the two 2gb for now, but.....then I read this on Bare feats: Some of you just want to buy two 2GB FB-DIMMs to add to the two factory 1GB FB-DIMMs for a total of 6GB. That configuration will slow you down. Don't do it. Again, the BEST performance setup is eight matched FB-DIMMs. The second best is four matched FB-DIMMs. What to do?