timer broken (was Re: fc5 hangs)

Two days in a row my fc5 computer has frozen soon after I start using it in the morning.

However, I have more information about the problem. I think I misdiagnosed the problem... it appears that the mouse/keyboard are not completely unresponsive... they're are just

responding extremely slowly.

I think I've discovered an important clue.?  I noticed the time
was frequently way off when this problem occurred, so I tried
cat /proc/interrupts | grep timer

The timer interrupt is incrementing very slowly.  Instead of
1000 Hz it's incrementing about once or twice per minute.  What
would cause that?  I had ntpd running, but I killed it.

The overnight average for my fc5 box was one timer
interrupt every ~32 seconds.  I left it running in case
somebody posted a diagnostic for me to try while it
was in this state, but no responses, so I rebooted it
this morning so I can start getting some work done.
It took about 10 minutes to reboot, but after it rebooted,
it was operating normally again (1000 Hz timer
interrupts) and good responsiveness.  Any thoughts
on why my timer seems to change to about 1/2^15
slower interrupt rate than usual?  IIRC, this system
is pretty much vanilla fc5.  I haven't installed any
RPMs that aren't from fedora updates or extras.

Thanks...

          David

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