Liquid-Cooled G5 Running Mac OS X 10.3.5
According to AppleInsider, pre-production models of the liquid-cooled dual processor 2.5 Ghz Power Mac G5 are running Mac OS X 10.3.5. While encountering key-command and 'artifacting' glitches, the OS is expected to ship in the new units, possibly prior to its public release.
Sources at WWDC said that the 2.5 Ghz units on display at the show were indeed running a pre-release version of 10.3.5. According to AI's sources, this update should be the most significant to the OS since the release of Panther.