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 on 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 2007.

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 virtualising server workloads to reduce power consumption and improve efficiency.

The shift will happen gradually, since 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 data centre 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 4G bytes of main memory without having to use technology tricks that diminish performance gains. A 64-bit OS can address far more memory -- up to 2T bytes 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 virtualisation, which allows multiple OSes and application loads to run on a single physical machine, and server virtualisation 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.

The 64-bit processors from Intel and AMD have maintained the x86 architecture from the 32-bit world. That means 32-bit applications can still run on 64-bit servers, and that "the majority of existing 32-bit applications will run aboard 64-bit Windows Server without modification and, most frequently, with improved performance," IDC said.

Customers will need to update low-level system tools such as security products, antivirus tools and some system-management products, which interact directly with the Windows Server kernel, IDC said.

At the end of 2007, the research company estimates, only about 10% of Windows Server customers were using the 64-bit edition of Windows Server 2003. It expects that figure to approach 50% by the end of 2010, driven by Windows Server 2008. For new licenses sold in 2010, close to 75% will be for a 64-bit version of Windows Server, IDC said.

Microsoft is keen to promote the transition to 64 bits. It will give its customers better performance and help Microsoft catch up with the Unix world, where powerful, but more expensive, servers from Sun, IBM and HP have long been based on 64-bit OSes. Microsoft believes the products launching this week will mark "a big turning point" toward the use of 64-bit Windows software, said Ward Ralston, a Microsoft senior technical product manager.

Microsoft also is pressuring independent software vendors to get their software 64-bit ready, after a lack of preparedness held back the transition after Windows Server 2003 was released. ISVs aren't required to have a native 64-bit edition of their software to receive a Certified for Windows Server 2008 logo, but they will need to assure their software can run on the 64-bit OS.

Some expect Microsoft's virtualisation technology, Hyper-V, to be a factor. The hypervisor will be offered free with the 64-bit edition of Windows Server 2008. Andrew Brust, head of new technology for the IT consulting company Twentysix New York, a Microsoft partner, said that Hyper-V "once it ships, is going to be huge. The virtualisation space is ripe for some new competition."

Brian Randell, a senior consultant with another Microsoft partner, MCW Technologies in Los Angeles, said Hyper-V will be a major impetus for the move to 64 bits. "It demands that you have that kind of processor environment available," he said.

However, others pointed to Hyper-V's immaturity. It was originally planned to ship with Windows Server 2008 but has been delayed for up to six months. Even then it will be Microsoft's first attempt at virtualisation, noted Michael Cherry, an analyst at Directions on Microsoft.

"I think there's too much emphasis on virtualisation with this release," he said. Hyper-V may eventually play a significant role for Microsoft, but the company first needs to develop the required tools for managing a complex virtualised environment. After the hypervisor is released, he said, Microsoft will also need to update its Virtual Machine Manager product.

Still, Cherry is upbeat about the new products, particularly Windows Server 2008. The redesign of the OS to allow customers to install only the functions they need for particular tasks, or roles, will provide security and maintenance advantages, he said.

He also pointed to the new Internet Information Server, which gives more options for running and controlling applications remotely, and a significant update to Terminal Services, which will make it easier to run line-of-business applications on a server and make them appear to the end-user as if they were running locally.

Twentysix New York's Brust said the new server products are "rock solid on 64-bit, and so too are the currently shipping versions of SQL Server, SharePoint and other server applications."

"When SQL Server 2008 ships, it will be the third version of the product to offer 64-bit support," Brust said. "Let’s face it, it’s time to move off 32-bit."