Major Clock Drift

[pardsbane at offthehill.org (Josh Pollak)]

I've got this strange problem on my Linux machine at work... We run ntp 
from a local server. Lately, my machine has developed some major clock 
drift. At bootup, it uses ntp to set the clock, but after only 24 
hours, the clock time can be as much as 3.5 or 4 seconds off from the 
server. This is a pain for my software development, since all my code 
is stored on the server and accessed via nfs, so make complains about 
clock skew.

Anyway, what could be the cause of my drifting clock? Could I have 
something setup wrong, or is my computer's hardware somehow going?

I'm running Gentoo.

-Josh