Proper Method of Time Sync?

[Jonathan Horne]

i have read about 2 methods to sync the time on a freebsd box.

1) add these entries to /etc/rc.conf:
ntpdate_enable="YES"
ntpdate_flags="us.pool.ntp.org"
... and let the system do a one-time sync at bootup, and rely on this
single method for timesync.

2) add this entry to /etc/rc.conf
ntpd_enable="YES"
add the file with these contents to /etc/rc.conf:
server us.pool.ntp.org
driftfile /var/db/ntp.drift
restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

so, i have a workstation and a server, which i originally did method 1 on,
but soon enough, time drifted quite a bit.  so i switched it to the 2nd
method, and they appear to be sync'd perfectly.  a third box i set up, i
did only method 2, and this one did not stay synced at all.  after i
manually ran 'ntpdate -v -b us.pool.ntp.org', this box straightend up.

are both methods required for proper time syncronization, or can one rely
only on the ntpd method?

thanks,
Jonathan Horne