Microsoft Windows client senior product marketing manager. Danny Beck told ZDNet Australia servers running the company's Web site and MSN Search and Messenger applications had been migrated to the 64-bit version of Windows Server 2003.
"Our MSN search engine is actually built on several thousand systems running the x64 version of Windows," Beck said. In addition, "the entire Microsoft.com site has been migrated, and we serve 30 million unique visitors every day."
Beck said the company had seen a 10-times performance gain from the MSN Messenger servers since they went 64-bit. The servers handle about 70 million messenger users.
However, while Microsoft is keen to tout the server version's stability, the desktop version might have some issues, hardware makers have said. In addition, Greg Sullivan, a lead product manager in the company's Windows unit, told ZDNet Australia's sister site CNET News.com that the desktop version "is not quite there" in terms of a market.
Sullivan said that for now, the desktop 64-bit Windows version is likely to appeal mainly to the hardest of the hard-core enthusiasts: people doing video rendering, or game development, for example.
Advanced Micro Devices (AMD) said around 40 percent of its Australian sales were of 64-bit processors. AMD's 64-bit CPUs have been available in the desktop segment of the market for around 18 months.
AMD senior engineer Michael Apthorpe denied his company was disappointed with the release, but did admit he thought Microsoft had focused on key performance drivers rather than the "fluffy niceties" of operating system design.
While Microsoft has notably not included 64-bit versions of some key programs -- such as Outlook Express and Windows Media Player -- in Windows XP x64, Apthorpe said the move wasn't important.
"You only need to port what's necessary," he said. "If you've got a little graphic interface and it looks real pretty and it's 32-bit, that's fine - it'll run. But when you need the 32-bit addressing, the bigger data space, certainly port that into 64-bit."
Microsoft agreed, saying in a statement: "Some applications such as non-memory intensive applications, do not necessarily benefit customers by being 64-bit native."
The company unusually chose to include both 32- and 64-bit versions of Internet Explorer in the release. The statement clarified the reason behind the move, saying it was "simply because 32-bit ActiveX controls cannot be run in the 64-bit version" of IE.
Microsoft's Beck said most Microsoft applications such as the Office suite would not be available in 64-bit versions until the end of 2006, when the company's next-generation operating system Longhorn is due for release.
Is longhorn 64-bit or 32-bit?