I just bought my first Mac, an 8-core 2.8 GHz Mac Pro, and I am looking to upgrade the RAM from the stock 2GB to 8GB. I think I remember reading that you get the best performance when you fiill all of the memory slots as opposed to just filling 1/2 of them. Is this correct? I thought you just had to install DDR2 memory in matched pairs. Is there an unlocked performance boost when all available slots are filled? I don't forsee myself ever needing 32GB of RAM before I would sell this machine and move on to another, but I can see myself putting 16GB in it. What would be the better upgrade, installing 4 x 2GB modules or 2 x 4 GB modules? With the former I would eventually fill all of the available slots for less $ whereas the latter option would leave open the possibility of putting 32GB in it and maybe be better for resale 5-6 years down the road due to the expansion opportunity. Am I overthinking this in trying to plan for the unknown?