Can you look at the System Event Log (SEL) and see if it is reporting any voltage, power, or temperature issue?
Is there any way to look at that without bringing down the server? It doesn't appear the sel viewer can be installed on a running Windows Server 2008 system.
I have looked in the Active System Console, and it is not showing anything in there. I have set it up to send me emails when it logs anything and I have not received any emails either.