Answer:
There are altogether 6 editions in Windows Vista. Except for Windows Vista Starter, the other 5 editions will be available in both 32-bit and 64-bit versions. First, let's look at the 2 editions that most of us won't be bothered with:
Windows Vista Starter Edition:
Like Windows XP Starter, this edition is only available in emerging markets such as India, Colombia, Thailand, and Indonesia - as a cheaper alternative to combat the rampant software piracy in those countries. Windows Vista Starter is not available in the United States, Canada or Europe. This edition has significant limitations, e.g. 32-bit only, allows the user to work on only 3 applications at a time, does not accept incoming network connections and a physical memory limit of 256MB. In addition, only AMD's Duron, Sempron and Geode processors, and Intel's Celeron and Pentium III CPUs are supported.
Windows Vista Enterprise Edition:
This edition is aimed at the enterprise segment, and is a superset of Windows Vista Business. Additional features include a multi-lingual UI, BitLocker Drive Encryption, and UNIX application support. Windows Vista Enterprise will not be available through retail or OEM channels, but only through Microsoft Software Assurance. Since this edition is a benefit of Software Assurance (SA), it will include several SA-only benefits, e.g. license allowing multiple virtual machines to run, access to Virtual PC Express, and activation via VLK. The 64-bit version will support up to 128GB of physical memory.
Windows Vista Home Basic Edition:
This edition is similar to Windows XP Home and is intended for budget users not requiring advanced media support. The Windows Aero UI with translucent effects is not included with this edition. The 64-bit Home Basic will support up to 8GB of physical memory
Windows Vista Home Premium Edition:
In addition to the features in Home Basic, this edition adds advanced multimedia features for the home market segment, such as HDTV support and DVD authoring. Also included are extra games, mobile and tablet PC, network projector, touchscreen and auxiliary display (via Windows SideShow) support, and a utility to schedule backups. Home Premium supports 10 simultaneous peer network connections (compared to 5 in Home Basic). The included Meeting Space will also allow for interaction (in Home Basic, you may only view meetings), but Remote Desktop sessions may only be received, not controlled. Home Premium is comparable to Windows XP Media Center Edition and the 64-bit version will support up to 16GB of physical memory.
Windows Vista Business Edition:
This edition is comparable to Windows XP Professional and XP Tablet PC Edition, and aimed at the business market segment. It includes all the features of Home Premium with the exception of Windows Media Center and related technologies, Parental Controls, and Windows DVD and Movie Maker HD (the regular Movie Maker is included). The additional features in Windows Vista Business is an IIS web server, fax support, Rights Management Services (RMS) Client, file encryption, dual processor (two sockets) support, system backup and recovery, offline file support, a full version of Remote Desktop, ad-hoc P2P collaboration capabilities, Previous Versions (Windows ShadowCopy), and several other business features not in Home Premium. The 64-bit version will support up to 128GB of physical memory.
Windows Vista Ultimate Edition:
Windows Vista Ultimate is the most powerful edition and targetted at the PC enthusiasts, gamers and power users. This edition combines all the features of Home Premium and Enterprise, and includes a game performance tweaker (WinSAT), special customer support services and exclusive downloads dubbed Ultimate Extras. The 64-bit version will support up to 128GB of physical memory.
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