Normally NTP slews the time if it’s off by less than 128ms, and steps the time if it’s over that. This can cause some serious problems with Oracle (especially 9i+). The -x option in xntpd forces all time changes to be slewed instead of stepped. You’ll want to run ntpdate if your time isn’t pretty close to being accurate already then make these changes:
stopsrc -s xntpd
chssys -s xntpd -a "-x"
startsrc -s xntpd