Binoculars,
The Mobo clocks are very inaccurate as Ian mentioned, that was the primary reason M$ added the clock sync to WinXP.
If you are sure there is nothing wrong with your system software wise, I would just go with the AnalogX's
Atomic Timesync. Mark Thompson does some really tight program coding that is some of the best you will ever find.
Take Care,
Richard