[c-nsp] Self rebooting pix?

[Scott Granados]

Hi All,
I'm having a strange problem and not much diagnostic output so maybe I can 
get some pointers as to what to look at next.

    I have a Pix 501 with a non restrictive license that I'm using as a 
general firewall and nat device.  There's a 10 megabit ethernet connection 
handing a statically routed Internet feed on the WAN side and a 100 megabit 
fast E which connects to a core switch.  We nat probably about 50 - 100 
users at a time and the throughput over the public pathway is less than 8 
megabits for the most part and generally stays around 3 - 5.  The output of 
show cpu usage shows a usage of between 10 and 20 percent with lows of 4% 
and highs around 25.
    Randomly through out the day the connection / device will hang, the 
switch it's attached to shows the ethernet port go down and come back up a 
few times then packets start to flow again.  After the most recent event I 
did a show ver on the Pix and saw that the uptime was less than 2 minutes. 
After each drop this counter returns to 0 which tells me the Pix is 
rebooting for some reason.  Show log doesn't yield anything interesting and 
the syslog server that captures the log output doesn't have any messages 
around the time of the outages either.  Total traffic disruption lasts for 
approximately 30 seconds.  The time of day is random and it does not seem to 
increase in frequency with bursts in traffic.  I've obviously checked and 
insure that the power cables are firmly attached and the network cables are 
securely attached as well.  What other things should I try?  Are there any 
other show commands that might yield some more clues?  Has anyone else 
experienced this.  The software rev is 6.3.

Thanks
Scott