Is Connector A of a PICMG 1.3 a regular X16 PCIE slot mechanically?

[iraqigeek]

Hi all,
I'm trying to build a "poor man's supercomputer" for machine learning. I want to connect about 8 Tesla P100 GPUs to my home server using a single X16 slot on the server and a PCIE backplane. While searching online, I found some industrial PICMG 1.3 backplanes that provide a lot of x16 slots mechanically (albeit they are x4 or x8 mechanically) using PCIE switches.

Looking here, I saw that Connector A on PICMG 1.3 is an x16 PCIE interface. The slot does look identical to regular x16 slots on the backplanes I found online. However, looking here (page 32) and comparing the pinout of an x16 slot I see the pins are ordered differently.

Am I reading something wrong here? or are the pins indeed ordered differently? Is anyone aware of an off-the-shelf riser cable that could connect a x16 slot on a regular motherboard to Connector-A on such a backplane for PCIE expansion?

 

[seany]

This might be a solution to your problem (though not your exact question).

In a sff project of mine in using these Delock Products 62863 Delock Adapter U.2 SFF-8639 > PCIe x4 with fixing plate to put full size cards in 1L PCs (via m. 2 adapters). I don't see a reason why you couldn't use them on a 8 port pcie switch card instead.

 

[alaricljs]

The "host" side of that backplane box is what is being described in the table. That backplane box requires a PICMG 1.3 board as the host. Without some form of converter cable to go from bog-standard PCIe x16 on a motherboard to this funky arrangement, you're not going to be able to use the backplane that you linked.

 

[iraqigeek]

thanks for the responses. I wanted to confirm if a regular PCIE rizer cable would work, and it seems it wouldn't

 

[iraqigeek]

This might be a solution to your problem (though not your exact question).

In a sff project of mine in using these Delock Products 62863 Delock Adapter U.2 SFF-8639 > PCIe x4 with fixing plate to put full size cards in 1L PCs (via m. 2 adapters). I don't see a reason why you couldn't use them on a 8 port pcie switch card instead.

I thought about something similar, using x16 to quad SFF-8643 adapter cards, and then SFF-8643 to x4 PCIe, but having 8 such adapters would make things quite clunky. Another option is something like C-Payne's bifurcation cards.

But a PCIe backplane would really be the cleanest option for cable management, if only such backplanes were available for an accessible price.