fast clock

We are running 7.1 , kernel 2.4.9-34smp
Several oracle db's
On an HP lh4-r

For no apparent reason the clock will start running very fast , as in
gaining 50 mins in an hour. 
We also run NTP , but this is unable to adjust the time correctly when it
starts racing..

The RTC time is correct when this occurs.

A reboot fixes the problem. 

There are no messages in the message's file or dmesg.

This occurred , last Sunday and the Saturday before that. Prior to that a
couple of months.

HELP !!!!!

 

Regards
Barry Surtees
Southern Cross Healthcare
Ph 356-0925 x 8863