Microsoft Windows XP Professional x64 Edition released on April 25, 2005 by Microsoft is a variation of the typical 32-bit Windows XP operating system for x86 personal computers. Windows XP Professional x64 Edition is based upon Windows Server 2003 SP1 (build 5.2.3790.1830) as that was the latest version of Microsoft Windows during the operating system's development, but takes Windows XP as its name. It is designed to use the expanded 64-bit memory address space provided by the AMD64 architecture; Intel refers to its implementation of the technology as EM64T.