For Windows Server 2008 R2, SP1 adds two new features that directly affect Microsoft's desktop virtualization platform: Microsoft Dynamic Memory and Microsoft RemoteFX. The former gives on-the-fly control of a virtual machine's memory while the latter provides a virtualized 3D graphical experience for remote users. For Windows 7, SP1 includes only minor updates: mostly hotfixes already delivered through Windows Update. SP1 will, however, feature an updated Remote Desktop client that takes advantage of RemoteFX introduced Windows Server 2008 R2 SP1.
11 months ago, Microsoft started testing SP1. A public beta was released in July 2010, followed by a public RC build in October 2010. The final release of SP1 was slated for the first quarter of 2011, but now we have a specific date to mark on our calendars. Microsoft provides service packs for free to bring its OSes up to speed with all of the latest security patches and bug fixes, provided that you have a genuine copy.