sp1 Service Pack 1 for Windows Vista was released to Windows Update today. We’ve been using it since the early beta versions, and we’ll share some of what you can expect when installing on your system(s).

If you remember XP SP1, you may be underwhelmed with Windows Vista SP1. However, that’s not necessarily a bad thing. Microsoft has been telling anyone who will listen that there’s no reason to wait for SP1 before installing Vista. They may have been right. While SP1 contains a number of improvements in performance, and overall quality; most of those have already been available through Windows Update.

Advances in Windows Update, as well as the widespread availability of broadband Internet means that you no longer have to wait for a service pack. Updates are introduced continuously. A service pack is just a roll-up of those updates conveniently packaged. Gone are the days of waiting for a service pack to introduce new applications, and features.

By the numbers, Windows Vista SP1 rolls together 23 security updates, and 550 hotfixes into a whopping 434.5MB download (726.5MB for the 64-bit version). It also includes some changes not previously addresses by Windows Update. If you have automatic updates enabled, Windows Update will gradually download the service pack to your system starting mid-April. Or, you can go to Windows Update and install it now.

It’s possible you may not see Service Pack 1 when visiting Windows Update. SP1 is currently available in only 5 languages. It requires some prerequisites to be installed via Windows Update first. Some drivers cause issues when SP1 is installed. So, if you’re running one of these drivers you won’t be able to install it until resolved. See the Windows Vista Blog for complete details.

The most notable fix in SP1 is probably the file copying improvements. It’s not only much faster, but estimates for completion will no longer display erroneous estimates of many years. Estimates are also calculated much faster making the entire file copy experience ‘feel’ faster.

Other changes include a tweaked User Account Control (UAC) that includes fewer prompts, although some may have hoped for even bigger changes to UAC. Windows Genuine Advantage (WGA) has adapted to address some exploits used by hackers to run unlicensed versions. If activation has not been successful in SP1, ‘Reduced Functionality Mode’ has been replaced with a notification mode.

If you haven’t installed Windows Vista, Service Pack 1 marks an important milestone. If you’ve already installed Windows Vista, SP1 corrects many of the frustrations, while improving performance and security. Retail packs and OEM installations will soon include Service Pack 1, negating the need to install it, or a number of Windows Updates.

Windows Vista has not enjoyed a great reception. While SP1 doesn’t address every concern, it has many welcome improvements, and support for future technologies. Many of the early problems deploying Windows Vista were related to drivers, and driver support is constantly improving. Windows Vista Service Pack 1 will see wide spread adoption by businesses. IT departments, and enterprise customers have been waiting for the bug fixes in Service Pack 1. Server 2008 and Vista SP1 share the same core (or kernel), and work better together. Retail prices have recently been lowered. There’s really never been a better time to upgrade to Windows Vista.