I recently upgraded my HP Proliant ML115 server to the latest BIOS version which is 2009.07.06 (A) (29 Jul 2009) I downloaded the firmware from here
When you initially boot up the ML115 it sounds like a jet plane taking off and is VERY LOUD! The problem was that after the BIOS update it was like this permanently which was driving my crazy. I did a bit of searching on the HP Support forums and it looked like i needed a new motherboard! Luckily i searched further and found that all I needed to do was to apply a further firmware update to the Lights out management interface on the server (even though i didn’t have one installed – go figure).
So if you experience this problem then go here and your server will be back to its silent operation after performing the firmware update 🙂