I believe the author is talking about the OCP (2.0) network card itself, that these adapters internally. The OCP nics are quite cheap compared to pcie - here’s 100GBE for 100!
https://ebay.us/m/HMQAph
This 100GbE card is an OCP 2.0 type 2 adapter, which will _probably_ not work with the PX PCB since that NIC has two of these mezzanine connectors, and PX only one.
What also may not work are Dell rNDC cards. They look like they have OCP 2.0 type 1 connectors, but may not quite fit (please correct me if I'm wrong). They do however have a nice cooling solution, which could be retrofitted to one of the OCP 2.0 cards.
I've also ordered a Chelsio T6225-OCP cards out of curiosity. These should fit in the PX adapter but require a 3rd-party driver on macOS (which then supports jumbo frames, etc.)
What also fits physically is a Broadcom BCM957304M3040C, but there are no drivers on macOS, and I couldn't get the firmware updated on Linux either.
That’s a good point to note! I think the stacking height would matter, but in theory the single connector is still 8x pcie and should link without the upper 8x lanes connected.
