My server has an Intel S2600CP2 Motherboard in an Intel P408XXMHEN chassis with 2 Intel E5-2609 Xeon CPUs with 8 x Intel certified KVR13R9D4/8i Kingston RAM modules with a single Intel 520s 480GB SSD and the optional airflow duct fitted.
When I first booted this system the fans were constantly running flat out and the system beeped with 1 normal beep followed with 3 short beeps. I tried installing the operating system (Windows Server 2012) which crashed and restarted the computer upon initialising. I have done some research on the internet and updated the Firmware to the latest available from the Intel site. This made a slight difference in that now 10 seconds after power on, the fans do settle down for about 30 seconds then go flat out again. Also the beep now appears to be 1 normal, 3 short and 1 normal. I am not 100% sure if this beep has changed as it is difficult to hear over the roar of the fans. Also Windows will now get to the first setup screen.
Along the way I have tried the system with a single CPU (tried both CPUs individually), tried each of the RAM DIMMs individually, disconnected the backpane, fans etc, none of which made any difference.
I cannot find any information on the Intel site (or anywhere else on the internet) that explains the beep code we are getting. I have also downloaded and attempted to run the EFI SEL viewer, which gets to the point where it says that it is gathering information to display but after 30 minutes nothing has happened and the fans are still roaring
You may want to apply the latest http://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=21918&lang=eng BIOS/Firmware to make the fans work properly You may also want to make sure the fans are connected to the correct fan headers. Your P4308XXMHEN comes with two fixed fans, and they should go to System Fan 1 & 2.
As for the beeps, those are expected when initializing USB devices. Nothing to worry.
I had already applied the latest BIOS/Firmware update but I did it again anyway.
I also set the BIOS setting "Set Fan Profile" to Acoustic and the "Quit Fan Idle Mode" to Enable.
I proceeded and installed windows after doing the BIOS upgrade again and the fans did settle down.
Your information about the beeping was good and the fact that sometimes I had a USB stick plugged in explained why sometimes I was getting OxxO and other times OxxxO. I originally thought that no matter what happened with the fans the beeping was indicating an underlying problem.
Anyway, all is good now, but if you have anything to add I will be happy to hear it.