With the release to manufacturing of service pack 1 (SP1) for Windows Vista, Microsoft’s newest client platform has passed the turning point beyond which adoption is expected to ramp up. But the consensus still seems to be that enterprises will only upgrade as and when they replace existing PC hardware.

Microsoft announced the RTM of Vista SP1 on 4 February, but said it will not be available to download and install until mid-March at the earliest, the same time as it will appear on new machines and in retail outlets.

While it has become an industry cliché that large organisations will not even consider a Windows version until the first service pack has been issued, this may be irrelevant in today’s connected world, where updates to software can be delivered to customers more easily and regularly, rather than through a monolithic service pack.

Mike Silver, research vice president for client computing at Gartner, said that Vista has arguably been getting better every month because of regular patches from Microsoft. However, he added that Vista is still not as stable as Windows XP SP2, which powers the vast majority of business clients.

But even if the release of Vista SP1 is not quite the big deal it would have been in the past, it is still a significant development.

Mike Haigh, Windows client marketing manager at Microsoft, described SP1 as “a milestone along the road, as opposed to a major change”, but also seemed to expect the update to encourage uptake.

“From a Microsoft perspective, there has never been a better time to upgrade,” Haigh said, adding, “It’s the culmination of a year of improvements, a great step forward in driver and application compatibility.”

There are no new features in SP1, but Microsoft’s BitLocker disk encryption tool has been made more flexible with the ability to encrypt disk volumes beyond the boot drive. Instead, SP1 has largely focused on fixing the early gripes with the initial release code of Vista.

“We know the major causes of dissatisfaction,” said Haigh. “Copying files was one, so we made some changes around the way files are copied over a network, and users should see up to a 50 per cent improvement.” The overall system responsiveness has also been addressed, as well as system reliability, he added.

When IT Week evaluated the release candidate (RC) of SP1 late in 2007, tests showed little evidence of any performance increase following the upgrade, but Haigh said that customers installing the final code “will see improvements over the RC or beta versions of SP1”.

Microsoft also claims that laptop users running Vista will see an improvement in battery life of about seven to 10 per cent after installing the upgrade.

There are many reasons why firms have been reluctant to start a migration to Vista, and among the most significant factors influencing decision makers is that Vista has few compelling new features that might drive businesses to migrate. Haigh said that this is changing, as people evaluating the new platform are now beginning to see productivity benefits that can be gained from improvements.

Richard Edwards, information management practice director at analyst firm Butler Group, argued that while there is definite business value in Vista’s new features, this did not balance up against the effort needed to make the move.

“There will be no mad dash for Vista,” Edwards said.

This situation may change in the near future once Windows Server 2008 (WS2008) becomes available. Microsoft claims that the combination of Vista clients and WS2008 will deliver key improvements, such as Network Access Protection, which ensures clients connecting to the network are compliant with security policies.

Vista clients will be able to cache resources from WS2008 servers locally, so that these are available offline, with copies automatically updating when the client and server are reconnected. Microsoft also claims that maintenance will be greatly simplified by the use of a single model for updates and service packs across Vista clients and WS2008 servers.

However, the other factor delaying Vista take-up is that the operating system is still much more resource-hungry than earlier versions of Windows, leading experts to advise that Vista should be acquired on new up-to-date hardware rather than deployed as an upgrade to systems running Windows XP.

For most companies, this will mean Vista creeping onto the network as systems are replaced by attrition or by planned hardware upgrades. Last year, Forrester Research predicted that Vista will be on a quarter of enterprise PCs by mid-2008, but other experts found this an optimistically high figure.

“Some IT managers already have Vista in their schedule, but we have found these are a tiny minority. For most organisations, SP1 is irrelevant, because they are not looking at Vista this side of 2010,” said Edwards.

But Gartner has warned in a report that firms need to start introducing Vista no later than 2009, because software vendors are likely to begin phasing out support for Windows XP after this.

The report also warned against skipping Vista in favour of its planned successor, Windows 7, which is due to ship in 2010. Companies are likely to find that migrating from XP to this platform is no easier than going to Vista, but that withdrawal of support might force their hand.

“Organisations that try to skip a version of Windows generally don’t have three or four years of support left on the old OS once they begin moving,” wrote Silver in the report. “We have seen the scenario time after time. Organisations that tried to skip Windows 98, Windows 2000 and Windows XP often had [software vendor] support issues and a difficult and often rushed or forced migration.”

The upshot of this is that most companies will end up having to deploy Vista, but that this may be a lengthy process.

While Windows XP will be supported with security fixes into 2014, application support is unlikely to extend that far. IT managers need to start preparing for Vista now, as the long slow retreat of Windows XP has already begun.