Driver Signing for Windows Vista/7/Server 2008/8 (x86 and x64)

Details about driver signing and signing mechanism for other code running in kernel mode privilege in Windows Vista or newer (both x86 and x64) is in this link: http://msdn.microsoft.com/en-us/library/windows/hardware/gg487317.aspx

I observed that x64 versions on Windows have a better kernel mode code authentication enforcement via driver signing compared to the x86 version.