I believe that there is a time clock you can connect to that works out the
error between successive synchronizations and applies a continuous
correction to the clock so that it becomes accurate. Only trouble is that I
can't remember its name. I think one had to install it as a server? Anyway a
Google search might find it. It claimed (if memory serves) to be the most
accurate way to keep all the PCs on a network in sync in circumstances where
small time differences could do damage.
Ah - I have it:
http://www.meinberg.de/english/sw/ntp.htm
Another thing to do is to shorten the time interval for synchronization from
the weekly default (every 604800 seconds) to daily (86400 seconds)
to do this go to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient\SpecialPollInterval\
and change it from 604800 to (decimal) 86400 seconds.
see for example at the foot of:
http://www.worldtimeserver.com/atomic-clock/
You could even resync hourly!
Doug