Okay so here's the deal... I just got my new G5 dual 2.0, and I bought some extra RAM from Crucial to add in. I ordered the computer with the bare minimum amount of RAM I could get (512MB) and ordered 3 more 512MB sticks from Crucial. I opened it up and installed the RAM, all 3 sticks on one bank (out of two banks with four slots each), which would mean one bank was full and the other had 3 empty slots. I booted up and checked "About This Mac" and it listed it as still having only 512MB, even though I had just installed 1.5 Gigs extra. I double checked the documentation and realized that I had overlooked the fact that the RAM has to be installed in pairs of equal size, one per bank, from the center outward. Swearing and cursing and kicking myself I shut down the computer and pulled all the cords again, opened it back up and rearranged the RAM properly, leaving one stick out as it wasn't part of a pair. So now with two sticks in each bay, properly seated and paired, I booted back up and checked "About This Mac" and it still lists the computer as having only 512MB! I went to System Profiler and it lists the slots that now have the Crucial RAM in them as empty. What am I doing wrong? I'm sure many of you have installed RAM and know the ropes better than I do, and I would be eternally grateful for some insight into this problem. Also out of curiosity, since RAM apparently has to be paired, does that mean I have to buy one more 512MB stick in order to use this other one that is not installed? Thanks a lot in advance.