I believe I have read, in more than one place, that MacOS9 only supports 1.5gb RAM, but in my 1.25GHz Dual G4 PowerMac MDD (no FW800) model, it recognizes 1.99gb of my installed 2gb RAM. My G4 came with a dual boot of MacOS9.2.2 & MacOSX10.2.6 on the same partition (which I did not know was possible, I thought 2 partitions were required for dual booting). Maybe it cannot access all 2gb of RAM, but MacOS9.2.2 shows it in the about this Mac menu item.