Recently bought a new MacPro for work. We use Leopard as our standard OS. Upon trying to load it on a new Quad 2.8 Mac Pro it wouldn't boot. Quickly called Apple. It took one of there techs about 5 minutes before he was able to confirm that the New 2010 Mac Pro's do not support any Mac OS previous to Snow Leopard. So FYI to those wondering. *Not sure about Boot Camp with versions Windows or Linux. I only use Mac OS.