This page is a work in progress, but contains some information on what has changed from SP1 to SP2 for Vista and Server 2008.
Hardware ecosystem support and enhancements:
Adds support for the 64-bit central processing unit (CPU) from VIA Technologies.
Integrates the Windows Vista Feature Pack for Wireless, which contains support for Bluetooth v2.1 and Windows Connect Now (WCN) Wi-Fi Configuration.
Improves performance for Wi-Fi connection after resuming from sleep mode.
Adds new capabilities to Direct X Graphic display reliability.
Includes updates to the RSS feeds sidebar with improved performance and responsiveness.
Improves audio and video performance for streaming high definition content.
Includes ability to record data to Blu-Ray media.
Operating system experience updates
Windows Search 4.0 builds on Microsoft’s search technology with improved indexing and search relevance. ce OneNote® 2007.
Improves Windows Media Center (WMC) in Content protection for TV.
Enterprise improvements
Provides the Hyper-V virtualization environment as a fully integrated feature of Windows Server 2008, including one free daughter OS with Windows Server 2008 Standard, four free licenses with Windows Server 2008 Enterprise and an unlimited number of free licenses with Windows Server 2008 Datacenter.
Provides an improved power management policy that is up to 10% more efficient than the original in some configurations (both on the server and the desktop), and includes the ability to manage these settings via Group Policy.
Improves backwards compatibility for Terminal server license keys. Windows Server 2008 changed the licensing key from 512 bytes to 2,048 bytes which caused clients using older Terminal versions to fail. SP2 allows legacy license keys on Citrix applications to work with Windows Server 2008 Terminal server.
Setup and deployment improvements
The SP2 standalone installer:
Provides a single installer for both Windows Vista and Windows Server 2008.
Includes the ability to detect an incompatible driver and block service pack installation or warn users of any potential loss of functionality.
Provides better error handling and descriptive error messages where possible.
Improves manageability through logging in the system event log.
Provides a secure install experience.
Includes the ability to service the installer post release.
