FYI....From HP...

DESCRIPTION
A limited number of HP ProLiant DL380 G6 servers with a system board with a revision level earlier than Rev 0S may unexpectedly reboot. The only message that is logged by server hardware or HP utilities is in the HP Integrated Lights-Out 2 (iLO 2) Event Log is as follows:

Server Reset, Server Power Removed, Server Power Restored
When this occurs, no hardware errors are logged, no events are captured in the Integrated Management Log (IML), and the server does not perform an Automatic Server Recovery (ASR); however, the operating system log will indicate that an unexpected reboot occurred.
The processor utilization of the server may affect whether or not it will unexpectedly reboot. This issue typically occurs when the server is idle in low power mode, although it can occur during normal operation.

SCOPE
A limited number of HP ProLiant DL380 G6 servers with a system board with a revision level earlier than Rev 0S that shipped prior to October 19, 2009 (10/19/2009) and has a server serial number prior to XXX924XXXX, where the fourth character is the year code and the fifth and sixth characters are the week code of manufacture.

RESOLUTION
For HP ProLiant DL380 G6 servers encountering unexpected server reboots, contact HP customer support.
• To obtain support in North America, contact Customer Support at 1-800-334-5144.
OR
• For Customer Support outside of North America, click on the following URL for a list of Customer Support Centers and appropriate phone numbers:
http://welcome.hp.com/country/us/en/wwcontact.html
HP support will perform all applicable troubleshooting and check all relevant logs to confirm that the issue described above is occurring. Once the issue has been validated, an HP authorized representative will come to the customer site to perform a CPLD code update for affected servers. 

HP is planning to release a firmware upgrade utility that will prevent this behavior which is currently targeted for availability on hp.com in late December 2009.