Microsoft on Tuesday confirmed that the next version of Office, code-named Office 14, will come in both 32-bit and 64-bit versions.
The 64-bit version is a first for both Office and for Microsoft's mainstream desktop applications, though a number of its server products, such as SQL Server, are already available in 64-bit versions.
Office 14, which is expected to be called Office 2010, is slated to ship next year. Among its other notable features is the fact that Microsoft will offer browser-based versions of Excel, PowerPoint, Word, and OneNote, in addition to the traditional Windows-based desktop programs.
By extending the browser support to Firefox and Safari, in addition to Internet Explorer, Microsoft has said it will have the effect of also bringing Office to the iPhone and to Linux-based computers for the first time.
Software designed for a 32-bit processor can still run on a 64-bit machine, but likely, the 64-bit version of Office will have some performance advantages over its 32-bit sibling when running on a 64-bit machine.
Computers with 64-bit processors have been shipping for years, but it is only in the last year or so that most new PCs have started to be sold with a 64-bit operating system--required for running a 64-bit application.
While most desktop applications still run only in 32-bit mode, the server side has switched over more quickly. Some of Microsoft's server products, such as Exchange 2007 the upcoming Windows Server 2008 R2, come only in the 64-bit variety.
The big selling point of 64-bit software is its ability to directly accommodate more than 4GB of physical memory.