It also means that Apple has made all the pieces of the OS that application developers need to tap into (mainly frameworks) ready and able to accept any 64-bit applications. In other words, Apple is paving the way for developers to create new Mac software that performs better, faster and more reliably.

One of the biggest accomplishments of Snow Leopard is that 64-bit and 32-bit applications can run side by side with no disruption to or input from the user. Launch a 32-bit app and it works; launch a 64-bit app next to it and it works. Users don't need to be concerned with whether an application is 32-bit or 64-bit -- they'll just notice that 64-bit apps run faster and may be a little bit more stable.

Note that not all Intel-based Macs (which are the only Macs capable of running Snow Leopard) are 64-bit machines. The first Intel Macs, released in early to mid-2006, were built around Intel's 32-bit Core Duo and Core Solo processors rather than the 64-bit Core 2 Duo and Xeon processors. While only a handful of models (the first Intel iMacs, MacBook Pros, MacBooks and Mac minis) contain the 32-bit processors, it meant that Snow Leopard and the apps that run on it had to be designed to run in either 32-bit or 64-bit operation.

Apple has done this in its own applications and other system components, and the developer tools it provides for Snow Leopard make it easy for third-party developers to create products that can run on either 64-bit or 32-bit Macs. If a user's Mac is a 32-bit machine, it will simply run Snow Leopard and all applications in 32-bit mode.