Way back in 2004, Microsoft released a little OS upgrade it called Service Pack 2. Windows XP owes much of its current popularity to the changes made in SP2. Although Vista is grabbing all the front-page attention with its soon-to-be-released Service Pack 1, XP hangers-on are hopeful that the upcoming Service Pack 3 can solve the nagging problems of software middle age.Early results show that SP3 might even provide a performance boost. So Vista may be hip, but XP is getting a hip replacement.

The XP SP3 Release Candidate is available now, with the final version set to ship in the second quarter of this year. (Whatever the actual date, you can bet that Vista SP1 will ship before XP SP3.) XP SP3 adds four new features. Only two seem really significant, one for corporate environments and one for the small-business/consumer side.

For the corporate world, XP SP3 will support the Network Access Protection (NAP) feature that is already available in Vista and Windows Server 2008. It allows IT managers to deny a PC access to network resources based on whether it's configured according to company policies. For example, if a PC does not have the latest antivirus signatures installed, NAP can limit its access so that it can only contact a remediation server that contains up-to-date signatures to be downloaded.

Given the concern that many companies have about security, the NAP feature could have been one that pushed them to upgrade to Vista. Now they can stay put with XP and still reap the benefits. It seems so much like the right thing to do that I can hardly believe that Microsoft has done it. Perhaps the goal is to sell more Windows Server 2008 licenses?

Consumers get a Vista feature transplant in XP SP3 with the ability to install without the need to enter a license key during setup. Within 30 days of installation, the user needs to enter a product key or XP will go in to a reduced-functionality mode similar to Vista.

The final two XP SP3 features seem relatively trivial: additional cryptographic providers, and enabling black hole router detection by default. XP already has the ability to detect black hole routers with a single change in the registry, so the feature here just seems to be that the setting will be enabled by default in SP3.

So, if these are the only new features and the rest of the changes are patches, why would SP3 be faster? It's a bit of a puzzle. Maybe the tests were anomalous, or perhaps there is a benefit from several non-security-related patches rolled into SP3 that haven't been previously released. Whatever the reason, it actually leaves me looking forward to this midlife OS boost.