We've seen there's a bit of confusion after a certain not-entirely-lucid portion of Steve's WWDC keynote yesterday, wherein he announced "top to bottom" 64-bit integration in Leopard, what he characterized as a first for the industry. As we all know, Apple is only shipping on one version of Leopard, so that led some to believe they'd be left in the lurch, their G4s, G5s, Core Solos, and Core Duos rotting on Tiger and unable to make the jump past 10.4. Thankfully, that ain't the case.
As we mentioned yesterday (but didn't really dig into), Leopard isn't entirely like Windows, where you're expected to install the 32 or 64-bit variants of the OS based on the system / CPU that will run it. We discussed this with Apple, which expressed that this latest version of OS X takes a far simpler approach for the end-user than multiple hardware-centric OS versions, opting instead to run both 64 and 32-bit apps and drivers on any 64-bit machine (read: Core 2 Duo-based), and defaulting to the usual 32-bit app / driver operation on 32-bit Macs. In other words, users with 64-bit capable Intel machines will see a performance boost if running 64-bit apps, but those that don't have a newer Apple box won't be at all penalized -- nor will they be unable to upgrade. So, we cool?