Microsoft has started offering Windows 7 Service Pack 1 (SP1) on Windows Update.
"Starting today, Windows 7 Service Pack 1 will be available to everyone via the Microsoft Download Centre and start rolling out via Windows Update," said Microsoft spokesman Brandon LeBlanc in a Tuesday post to the Windows blog .
When delivered via Windows Update, Windows 7 SP1 weighs in at approximately 750MB for the 32-bit version, just over 1GB for the 64-bit edition.
A much larger version is available on Microsoft's download site for users needing to upgrade multiple machines.
Microsoft announced Windows 7 SP1 almost a year ago, delivered a public beta of SP1 in July 2010 and then followed that with a "release candidate" build last October.
Microsoft has said several times - and repeated today - that Windows 7 SP1 does not include new features, but instead is a collection of security patches and nonsecurity fixes that have already been issued via Windows Update.
The only additions to SP1 include an updated Remote Desktop client designed to work with RemoteFX, a new technology that debuted with Windows Server 2008 R2 SP1, which has also shipped. RemoteFX is designed to improve the graphics performance of Windows 7 virtual machines hosted on Server 2008 R2 SP1 systems. Windows 7 SP1 also supports "Dynamic Memory", a feature in Server 2008 R2 SP1 that lets IT staff adjust guest virtual machines' memory on the fly.
Windows 7 SP1 can be uninstalled by selecting the "Service Pack for Microsoft Windows (KB 976932)" item using the operating system's control panel and uninstall tool.