Connectx-9 in pci gen5 server

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

one of the differences between the cx8 and cx9 is that the cx9 supports a single stream of 800GE (vs IB). I am wondering if this is only useful for a pci gen6 server. the reason I ask is that for the cx8, I am able to get 800Gbps via the aux cable and the extra 16 lanes of pci gen5. this creates 2 different pci ids. That seems to force 2 x 400GE interfaces. Does the same happen with the cx9?

2

Hi,

The same for CX9, once use aux cable, the OS will see 2 PCIe device

Thanks,

Suo

3

thank you for the quick response. Can you tell me if there are any differences between the cx8 and cx9 when used in a pci gen5 server then? I was hoping that the cx9 would be able to have a single stream of 800Gbps for Ethernet vs the cx8 that is split into 2 x 400G when in Ethernet mode.

4

Hi

I just get the confirmation from engineering team, there is no issue to support 800G using Gen5 over x32 PCI lanes (socket direct)

Thanks,

Suo

5

Just to be clear, you mentioned that there is “no issue to support 800G using Gen5…” My specific question is: Is there a difference in how the cx9 and cx8 nics present themselves when in Ethernet mode in a gen5 server? ex. cx8 presents as 2x400GE but cx9 presents as 1x800GE?

6

CX9 can present as a single 800G, whereas CX8 only supports two 400G connections.