The PCI mezzanine is a carrier for the PCI-X and PCIe cards. Remove the PCI mezzanine to replace the following components:
LED board
Alarm board
FB-DIMMs on the motherboard
Motherboard assembly
Power distribution board (PDB)
It is not necessary to remove the PCI mezzanine for other components. However, when the PCI mezzanine is removed, additional working space is provided.