According to the specs, the IGX Developer Kit has a two full-width PCIe Gen5 slots (one trimmed to x8) to support discrete GPUs like the RTX A6000. However, judging by the listed module specs and the 248 TOPS, it probably uses the Jetson AGX Orin™ Industrial SoM, which only has 24 PCIe Gen4 lanes; and can only be configured to use two x8 and one x4 controllers according to the Orin TRM. Therefore, I’m assuming that the attached GPU would always be trimmed to 8 lanes.
Could someone from NVIDIA please clarify if that’s the case?
Currently only the A6000 dGPU is supported. Currently other dGPUs have not been HW or SW tested in the platform. At some point we will expand the list of supported dGPUs for the IGX Orin.
Things are connected as follows:
The IGX Orin Industrial SoM is connected to the PCIe 5 switch on the embedded ConnectX-7. This link is currently a PCIe4 x8 connection but can support PCIe 5 with future SoMs.
The ConnectX-7 has a PCIe 5 x32 way switch embedded in its silicon. This provides connections for the NIC, the 2x PCIe slots and the SoM itself.
PCIe Slot 1 is a PCIe 5 x8 slot with x16 physical. We would not typically recommend this slot for dGPU usage but it’s fine for other PCIe devices
PCIe Slot 2 is a PCIe 5 x16 slot. This slot would typically be used for dGPU usage. A6000 is currently the only tested and supported dGPU.
All communications paths are supported eg. NIC to SoM, NIC to dGPU (ie. GPUDirect functionality) and SoM to dGPU etc. During IGX bringup you get to decide whether you wish to operate using the dGPU or the iGPU embedded in the SoM. At some point we will support dual-mode running.