Murray, I clipped this last week from MacNN. Here is where things seem to stand at the moment. Bill Montreal "With a public release of Leopard due at some point in October, Apple must finalize the operating system within weeks, and so may be considering its latest version as a possible final build. The Mac OS X 10.5 Leopard pre-release version for developer testing currently lists system requirements as a G4 867MHz or faster processor, which makes several older Mac models incapable of running the forthcoming operating system."