How do you physically connect two downstream PCIEx16 cards to the ConnectX-8 DTO

Infrastructure & Networking Adapters and Cables InfiniBand/VPI Adapter Cards
1

if i plug the ConnectX-8 to a server pcie slot and want to connect 2 x16 devices downstream, are there off the shelf components one can use (Cable, MCIO/PCIE adapter) that will allow full x16 connectivity to each of the downstream pcie cards? I’m assuming (need confirmation) that the MCIO port has 32 PCIe lanes available for downstream use

2

Hi owais5,

Yes, the ConnectX-8 DTO is designed exactly for this use case. The card exposes two downstream MCIO (Mini Cool Edge IO) x16 ports, each providing full PCIe Gen 5 x16 connectivity to a downstream device independently - no lane sharing
between the two.

To physically connect two PCIe x16 cards downstream, you need:

  1. MCIO x16 to PCIe x16 cable - connects the DTO’s MCIO downstream port to a riser/adapter.
  2. MCIO to PCIe x16 slot riser/adapter card - provides a standard PCIe x16 slot for your downstream card to seat into.

Typical setup:
Server PCIe slot
│
ConnectX-8 DTO (upstream PCIe x16 to host)
├── MCIO Port 0 ──[MCIO x16 cable]──> PCIe x16 riser ──> Card A
└── MCIO Port 1 ──[MCIO x16 cable]──> PCIe x16 riser ──> Card B

A few things to keep in mind:

  • Power: The MCIO cable carries PCIe data only - your downstream cards will need independent power via the riser card’s PCIe slot power + any auxiliary power connectors.
  • Cable length: Passive copper MCIO cables typically support up to ~1m. For longer distances, active copper or optical cable assemblies are available.
  • Form factor: Make sure the riser adapter matches your downstream card’s physical size (full-height vs. half-height, etc.).

Thanks,
Ilan.