All Microsoft Windows versions since Windows 2000 include the Windows Time service ("W32Time"),[22] which has the ability to synchronize the computer clock to an NTP server.
The W32Time service was originally implemented for the purpose of the Kerberos version 5 authentication protocol, which required time to be within 5 minutes of the correct value to prevent replay attacks. The version in Windows 2000 and Windows XP only implements SNTP, and violates several aspects of the NTP version 3 standard.[23] Beginning with Windows Server 2003 and Windows Vista, a compliant implementation of full NTP is included.[24] Microsoft says that the W32Time service cannot reliably maintain sync time to the range of 1 to 2 seconds.[25] If higher accuracy is desired, Microsoft recommends using a different NTP implementation.[26]
Windows Server 2016 now supports 1 ms time accuracy under certain operating conditions.[27]