 Both "Windows Server 2003 x64" and Windows XP Professional x64 Edition use identical kernels.Windows XP "Professional" "x64 Edition" is not to be confused with Windows XP "64-bit Edition", as the latter was designed for Intel Itanium processors.During the initial development phases, Windows XP Professional x64 Edition was named "Windows XP 64-Bit Edition for 64-Bit Extended Systems".