Hi I'm trying to sell my old mac pro (with no AppleCare), but I want to get all of the problems figured out so nothing comes up after the buyer buys it. My RAM configuration is as follows: 2x2GB, 4x1GB It never reads the correct amount of ram (8GB). It fluctuates between 2GB and 6GB depending on my configuration, but recently it's only been 2-4GB. I'm currently troubleshooting which RAM trays/RAM slots/RAM sticks are giving me problems. It's looking like only the innermost two slots on the upper RAM tray are working. It doesn't matter which tray i insert on the upper tray slot. It only recognizes the innermost two slots. I've done many AHT hardware tests on the logic board (well, the entire computer), which haven't found any problems. That said, it looks like both my trays are okay, and all of my RAM sticks are okay, just the computer is only recognizing those inner slots. Any advice? Could it possibly just be a software issue, or is it looking like a problem with the LB? I just really don't want to carry my Mac Pro all the way to the Apple Store. (I have to walk there) Thanks in advance!