net6501 clock drift

Hello,

We have a bunch of net6501 boxes around here. The hardware clock suffers
from quite high clock drift (4 to 10 secs a day, depending on the box).

We are using NTP, so the soft clock is in sync (this is how we
discovered the hw clock drift). But when the boxes reboot, the soft
clock starts from the hw clock, and getting back to sync takes time (up
to several days).

Is such a big hw clock drift usual on 6501 ?
-- 
Mbdr