CentOS 5.5 - kernel panic - Help!

[tmcallaghan-Re5JQEeQqe8AvxtiuMwx3w at public.gmane.org (Tim Callaghan)]

I'm trying to track down the source of a kernel panic that I see once
or twice a week on one of my CentOS machines, specifics:
  CentOS 5.5
  ASUS p6x58d Motherboard
  Intel i7-920
  3 x Corsair X3 2GB
  WD 1TB 6Gb SATA - OS drive
  Intel X-25M SSD - data drive for DB benchmarking

After running for a few days, the machine fails to respond to ping.
When I look at the console I see "kernel panic - not syncing - nmi
watchdog".  Nothing is logging to /var/log/messages, when I open the
file after lockup I see the log usual information plus all the new
restart info.

I used this machine prior with Ubuntu 9.10 and 10.04 and would
occasionally experience lock-ups as well, I just never tried to track
them down when running Ubuntu.  I need it to be stable now.

I'm considering booting with "nmi_watchdog=0" but concerned that I'll
just be masking a real issue.

Any ideas?

-Tim