4 servers, 4 cpu = 1 per board?
Guess #1
Did you install the CPU in the slot in the middle of the board?
Center CPU is the boot processor.
Guess #2
What BIOS version is on the board?
It is hard to tell, but there is a tiny white sticker on top of the BIOS flash chip. Should say R01.08.xxxx or higher for V2 CPUs.
It can also be looked up if you have the boards part number.
Less than R01.08.xxxx will only boot V1 processors. (If you have a V1, you can boot and update the BIOS code stack, then switch back to the V2)