This message was posted on behalf of Intel Corporation
The Intel® Server Board S2600ST Product Family offers SFP+ 10Gbps connectivity, through and optional LAN riser accesory card. The network controller is integrated into the Platform Controller Hub (PCH) and the riser accessory provided the physical interface. The two "additional" NICs listed in device manager are the ones integrated in the PCH.
The SFP+ LAN Riser option is only supported when installed into PCIe add-in slot #5 on the server board which includes an expansion connector allowing for communication to the onboard PCH and BMC. The SFP+ LAN Riser option can be used in single or dual processor configurations.
For further references please check the Technical Product Specification from the link below:
The problem is...
There is NO riser card in the machine...in fact there aren't any cards at all. But 4 NICs still show up in the device manager. The 2 onboard NIC..and the 2 SFP+ NICs
Reading the FRUSDR notes...The FRUSDR should disable the 2 SFP NICs if the module is not present. That is not happening
We replaced the main board and the second board had the same problem
There is definitely an issue with this board
As stated in the prior message, the 2 SFP NICs are going to be detected by the Operating System, even with no riser card installed. The network controller is integrated into the Platform Controller Hub (PCH), that is the reason why they are still listed in device manager. If the FRU/SDR update is not disabling them, we can suggest you wait for an update to the firmware package.
Since this is an embedded feature from this server board family, a replacement is not going to get rid of the two additional NICs.