While a 64-bit version of Mac OS X lags behind by Apple Power Mac G5 by a few months, the new system ships with OS X 10.2.7 (G5) – code-named Smeagol.
Relying on a 32-bit version of OS X limits OS performance gains in the initial release – missing out on some of the advantages of its key new features. 10.2.7 therefore delivers OS X performance at least equal to what Jaguar achieves on the G4. Smeagol is, however, said to take advantage of the new processor's fast frontside bus and cache.
Mac OS X 10.3 Panther will be able to take advantage of all the new processor's capabilities.