The PCI mezzanine is a carrier for the PCIe2 cards in slots 4 and 5 and the SAS controller HBA. Remove the PCI mezzanine to replace the following components:
PCIe2 cards in slots 0, 1, and 2
Motherboard assembly
CPU modules
Flash modules and Flash module cable
ESM riser and ESM
Battery
It is not necessary to remove the PCI mezzanine for other components. However, when you remove the PCI mezzanine, you make additional working space available.