The 64-bit editions of Windows Vista come with inherent pluses in comparison with the 32-bit versions, from tailor fitting the next generation x64 processor architecture to breaking down the limitations associated with x86 memory addressing, and opening your options to a total of 128 GB of RAM. Windows Vista Home Basic, Home Premium, Business and Ultimate in the 64-bit flavors share similar installation options.

The same is not the case for Windows Vista Starter and Enterprise editions. However, as far as Vista is concerned, users can choose between upgrade and clean install when it comes to deploying the operating system.

There is a range of operating systems that are eligible for a 64-bit Windows Vista upgrade. According to Microsoft, users of Windows 2000, Windows XP Professional, Windows XP Home, Windows XP Media Center, Windows XP Tablet PC, Windows XP Professional x64, Windows Vista Home Basic (32-bit and 64-bit), Windows Vista Home Premium (32-bit and 64-bit), Windows Vista Business (32-bit and 64-bit) and Windows Vista Ultimate (32-bit and 64-bit) are all eligible to be upgraded to an edition of x64 Vista.

Essentially, an upgrade is an in-place installation of Vista designed to keep in place files, settings, and programs. By contrast, a custom (clean) install will wipe the hard drive clean of any trace of an older Windows platform together with all the adjacent applications and user configuration. The main thing that users have to keep in mind when deploying Vista via an upgrade media is that they will need to keep the previous Windows operating system in place because of the licensing information associated with it.

Additionally, users should also be aware of the fact that while a 32-bit operating system integrates seamlessly with a 64-bit architecture, the same is valid for 64-bit platforms on 32-bit architectures. In this context, a 64-bit flavor of Vista can only be installed on a 64-bit system.