In a development that should surprise only the pathologically naive, the Vista service pack 1 RTM has found its way onto Web download sites like BitTorrent and Pirate Bay. But it turns out that the Vista SP1 RTM has most likely been floating around the Web for a couple of weeks.

On Thursday, a Microsoft spokesperson confirmed that the Vista SP1 RTM is identical to the most recent build of Vista, Vista SP1 RC refresh 2, which Microsoft made available on January 24 to a group of 15,000 beta testers.

"In the final stages of a product, we like to get as much validation as possible before releasing. The release candidate ended up being of a high enough quality to be approved to release to manufacturing," the Microsoft spokesperson said in an email.

Earlier this week, Microsoft announced that Vista SP1 had reached RTM, but that partners and developers, including those with paid subscriptions to MSDN and TechNet, wouldn't be able to download it until mid-March because of device driver issues.

But apparently, users who can't wait to get their hands on the SP1 bits they crave have been heading online. As of Thursday afternoon, one popular BitTorrent site, Mininova, showed six files labeled as Vista SP1 RTM as available for download, ranging in size from 434 megabytes to 2.87 gigabytes. One file had 159 seeds and 665 leeches, but user comments indicated that it wasn't the actual Vista SP1.

Last month, several BitTorrent users were duped into downloading files that were billed as early builds of Windows 7, the successor to Vista which Microsoft plans to release sometime in late 2009.

Tom DeRosier, co-owner of CPU Guys, a Hanson, Mass., system builder, says Microsoft is well aware that the Vista SP1 RTM would be posted to the various Web file sharing sites.

"You need testers to see how the software runs in the real world. That's not a bad thing, and it may work in Microsoft's favor. It's almost as if they're letting the world do the R&D for them," DeRosier said.