ABOUT THE SYSTEM SYSTEM FEATURES
1-3
Expansion slots
Riser Slot1 (x24):
Gen3, PCIe x 8, CPU1 (Full Height Half Length Card*)
Gen3, PCIe x16, CPU0 (Full Height Half Length Card)
Riser Slot2 (x16):
Gen3, PCIe x16, CPU1 (reserved for SAS mezzanine card type B installation)
Riser Slot3 (x32):
Gen3, PCIe x16, CPU2 (MD2 Low-profile Card)
Gen3, PCIe x16, CPU2 (MD2 Low-profile Card)
Riser Slot4 (x24):
Gen3, PCIe x 8, CPU3 (MD2 Low-profile Card*)
Gen3, PCIe x16, CPU3 (MD2 Low-profile Card)
*not available while FHFL card installed (only for GPU SKU)
OCP Mezz Slot (x16): 
Gen3, PCIe x16, CPU0 (OCP 2.0)
(This OCP mezzanine slot is available for GbE/10GbE PHY card installation.)
Table 1.1: System Specifications (Continued)
SPECIFICATIONS DESCRIPTION
Riser slot1 (x24)
*not avaiable while x16 FHFL card is installed (only for GPU SKU)
C
B
Riser slot3 (x32)Riser slot4 (x24)
OCP slot 
A
Mainboard
Riser slot2 (x16)
(SAS mezzanine)
x8* (MD2)
x16 (MD2/FHFL)
x16 (MD2)
x16 (MD2)
x8* (FHHL)
x16 (FHHL/FHFL)
(Reserved)
* il bl hil FHFL d i* il bl hil FHFL d i