Vista SP1, likely to be released to manufacturing in the first quarter of 2008, will not be as significant a feature release as Windows last major operating system service pack, Windows XP SP2, the company indicated in a set of press releases and blog postings.

Rather, it will roll up many of the incremental performance and security updates Microsoft has been making to the software since its release to corporate customers last November.

We’re targeting releasing SP1 to manufacturing in the first quarter of 2008, but as always, we’re first and foremost focused on delivering a high-quality release, so we’ll determine the exact release date of SP1 after we have reached that quality bar, Vista product manager Nick White blogged.

SP1 will contain changes focused on addressing specific reliability and performance issues we’ve identified via customer feedback, supporting new types of hardware, and adding support for several emerging standards, he wrote. SP1 also makes additional improvements to the IT administration experience.

While the company discussed no new features per se, existing features will be updated. For example, the BitLocker Drive Encryption tool, new to Vista, will be changed to allow users to encrypt multiple disk volumes, not just C:, Microsoft said.

Copying and extracting files will be faster, Microsoft said. Recovering from hibernation will also be quicker, as will Internet Explorer 7 running JavaScript. Using file shares and logging in have also been tweaked to improve performance, the company said.

Microsoft is also making much of the fact that, in this age of ongoing OS improvements over channels such as Windows Update and Server Update Services, a new service pack should not be as critical a hurdle as it used to be for companies thinking about upgrading.

Organizations do not need to wait for SP1 to deploy Windows Vista; they are encouraged to begin their Windows Vista evaluation and deployment now, the company said in a white paper on SP1.

That was perhaps an inevitable line for Microsoft to take, given how entrenched the Wait for SP1 sentiment has become in businesses since Vista’s release.

Most recently, a small survey of IT managers conducted by Forrester Research found that most respondents are waiting for SP1’s release before seriously considering their upgrade plans. Application compatibility and hardware requirements remain key concerns.

SP1 has been in beta preview with a select group of testers for some weeks. A formal beta will be released to a wider audience in the next few weeks.

While Microsoft has not put a firm date on the release of SP1 gold, the company did say yesterday that its development is being coordinated with ongoing work on Windows Server 2008, which is scheduled for a February 27 launch.