Hello, I bought a PowerMac Gigabit Dual 450 on eBay, great machine. With some research into upgrades, graphics card and SATA card, i discovered on macupgrades.co.uk that apparently this machine can address a full 2GB of RAM on OS X. (Four slots) I was unaware of this before i bought it, and i'm quite chuffed really as even the models after it can only address 1.5GB of RAM. That's including the quicksilver. So if any of you have a Gigabit Ethernet with Dual processor, you might benefit from an extra 512 of RAM. Rich.