Windows XP Service Pack 3 (SP3) build 5512 was released to manufacturing on April 21, 2008 and to the public via both the Microsoft Download Center and Windows Update on May 6, 2008.
It began being automatically pushed out to Automatic Update users on July 10, 2008. A feature set overview which details new features available separately as standalone updates to Windows XP, as well as backported features from Windows Vista has been posted by Microsoft. A total of 1,174 fixes have been included in SP3. Service Pack 3 can be installed on systems with Internet Explorer versions 6 or 7, and Windows Media Player versions 9 and above. Internet Explorer 7 is not included as part of SP3.
 New features
* Turns Black hole router detection on by default 
* Network Access Protection client
* Windows Imaging Component 
* Credentials Security Service Provider 
* Descriptive Security options in Group Policy/Local Security Policy user interface
* An updated version of the Microsoft Kernel Mode Cryptographic Module that is FIPS 140-2 certified 
* Installing without requiring a product key during setup for retail and OEM versions
Slipstreamed retail and OEM versions of Windows XP with SP3 can be installed and run with full functionality for 30 days without a product key, after which time the user will be prompted to enter a valid key and activate the installation. Volume license (VLK) versions still require entering a product key before beginning installation.
Although service packs have, until now, been cumulative, installing SP3 on an existing installation of Windows XP requires that the computer must at least be running with Service Pack 1 installed. However, it is possible to slipstream SP3 into the Windows XP setup files at any service pack level—including the original RTM version—without any errors or issues. Slipstreaming SP3 into Windows XP Media Center Edition 2005 is not supported.
Service Pack 3 does contain updates to the operating system components of Windows XP Media Center Edition (MCE) and Windows XP Tablet PC Edition, and security updates for .NET Framework version 1.0, which is included in these Windows XP SKUs. However, it does not include update rollups for the Windows Media Center application in Windows XP MCE 2005. SP3 also omits security updates for Windows Media Player 10, although the player is included in Windows XP MCE 2005. The Address Bar DeskBand on the Taskbar is no longer included due to legal restrictions.