Service Pack 1 for Windows 7 available for download
As expected, Microsoft has made the first Service Pack for Windows 7 and Server 2008 R2 available for download and started to distribute it via Windows Update. Currently only an ISO file is available for standalone download. It contains the complete packages for x86, x64 and Itanium. Separate packages should be available shortly, with links for downloading x86 and x64 already operative. The 32-bit package is around 550 MB, the x64 package 925 MB and the ISO image just under 2 GB.
The complete package (which Microsoft designates as a "network installation package") contains the complete set of patches and hotfixes and will ensure that a newly installed copy of Windows is fully up to date. However, on our 32-bit test system installation, SP1 required prior installation of a further update (KB947821). The complete package is intended primarily for administrators who need to get SP1 onto multiple systems.
Users wishing to update single Windows installations to SP1 are advised to download SP1 via the Windows Update function, which downloads only what is necessary to bring the system to the current patch level and avoids downloading patches which have previously been installed via Windows Update. The result is a much smaller download.
SP1 is primarily a collection of hotfixes and patches, an overview of which Microsoft has provided here. There is little new functionality – Microsoft cites just RemoteFX (hardware accelerated 3D graphics output in remote desktop sessions in conjunction with Server 2008 R2 only) and Dynamic Memory (dynamic allocation of main memory to guest systems under Windows Server 2008 R2 Hyper-V). Service Pack 1 also adds support for AVX to the latest version of Windows; AVX is an instruction set extension used in some more recent processors.
Users wishing to prevent SP1 from being installed automatically via Windows Update can use Microsoft's blocking tool. It prevents automatic installation of SP1 for a period of one year. To date, however, there appears to be no real reason to decline to install SP1 – not that there is any pressing need to install right away either, since, as long as Windows Update is not deactivated, all security-related patches should already be installed.
Microsoft provides further information on SP1 here, which also includes further links to the official sites for downloading complete stand-alone packages.