Since yesterday I didn't understand what W32Time do even if I discussed with Max about it, today I decided to search around in order to learn more.
As far as I understood W32Time.exe is based on the Simple Network Time Protocol (SNTP, a protocol designed to ensure loose synchronization), is installed as part of Windows XP and Windows Server 2003 default installations and is associated with the Windows Time service.
W32Time synchronizes clocks within a forest using a time hierarchy that begins with the PDC Emulator in the forest root domain, which is considered the stratum 2 time source for the forest.
If you want to ensure that the clocks on your machines are more accurate in terms of absolute (and not just relative) time, you can sync the PDC Emulator in your forest root domain to one of the reliable time servers available on the Internet; modify registry as documented here: http://support.microsoft.com/kb/q223184/ then restart the Windows Time service.
It may take an hour or so for the PDC Emulator to fully synchronize with the external time server because of the nature of the polling method W32Time uses. Depending on the latency of your Internet connection, the accuracy of the CMOS clock on your forest root PDC Emulator may be within a second or two of UTC.
If you don’t want to wait for time convergence to occur between your stratum 2 time server (your forest root PDC Emulator) and the external stratum 1 time server, you can run the following command on your PDC Emulator: w32tm /resync /rediscover
More details here:link1 and link2.