The launch of a new family of Windows server products this week will kick-start a broad shift among customers to 64-bit versions of Microsoft's server software, analysts and customers said.

Microsoft CEO Steve Ballmer is due to launch two major product upgrades at an event Wednesday in Los Angeles -- the Windows Server 2008 OS, which is due for release next week, and its SQL Server 2008 database, expected in the third quarter after delays. He's also expected to discuss Visual Studio 2008, which shipped in November.

Like their predecessors, the new products will be offered in both 32- and 64-bit editions. But several factors this time will prompt more customers to choose the 64-bit versions, including the broad availability of 64-bit x86 server hardware and the trend toward consolidating and virtualizing server workloads to reduce power consumption and improve efficiency.

The shift will happen gradually because most customers are not expected to deploy the products widely until next year. But it will mark a significant maturation for Microsoft's server products, which long were seen as an also-ran in the datacenter beside 64-bit Unix OSes from companies such as Sun and HP. It should also mean better performance for Microsoft customers.

"This will absolutely tip the scales in terms of more 64-bit deployments moving forward," John Enck, a vice president and research analyst with Gartner, said of the new products. The move will be driven by a desire among customers to get the most out of their 64-bit server hardware, he said, which means using a 64-bit OS.

The difference lies in the amount of physical memory the software can address. A 32-bit OS can address only 4GB of main memory without having to use technology tricks that diminish performance gains. A 64-bit OS can address far more memory -- up to 2TB in the case of Windows Server 2008, according to Microsoft.

That will boost the performance of some applications because they will be able to pull data quickly from main memory instead of having to retrieve it from disk, which is slower. The gains should be evident for databases and for Microsoft's Exchange Server, although line-of-business applications will see less benefit, Enck said.

Customers may also be driven to 64 bits by concerns about the future. Microsoft has said this will be the last big upgrade to Windows Server offered in both 32- and 64-bit editions, and some expect the same to be true for SQL Server. Exchange Server 2007, released in November, already is available only in 64 bits. Customers would be wise to start preparing now for a move that soon will be forced upon them anyway, analysts said.

Also propelling the move is the trend toward server consolidation. One option for that is virtualization, which allows multiple OSes and application loads to run on a single physical machine, and server virtualization requires the capacity of a powerful, 64-bit server.

"Anybody doing a deployment today would be foolish not to at least consider when and where a 64-bit OS would be a good fit," said Al Gillen, a research vice president with IDC. "It's really about future-proofing your IT environment, giving yourself the ability to support the workloads that you'll have on these servers before they are retired in five years' time."

IDC has called the lack of adoption of 64-bit Windows Server "one of the biggest missed opportunities among today's customer base." It notes that the 64-bit products will be priced the same as their 32-bit counterparts and argues that the transition is relatively easy for customers.