[PLUG] PCI cards and connectors

[Linh Pham]

PCI Express cards typically come as x1, x4, x8 and x16 (number of lanes)
and the connectors correspond to the number of lanes and the same with
PCI Express slots.

Some, but not all, PCI Express slots have an open end to accept cards
with more lanes than the slot is wired up for. But, the majority of the
slots are not open-ended and can only accept cards for that connector's
length or shorter.

For instance, a close-ended x4 can only accept a x1 or a x4 card.

What's even more fun is that a slot can be wired for fewer lanes than it
can actually physically handle. Thunderbolt docks are commonly that way
due to TB3 supporting a maximum of a x4 connection.

Based on what I found on B&H, one slot is a x16 slot that's wired up
for x8 and two x8 slots. How that's wired up to the controller/PCIe
switch, I'm not sure.

- Linh

On 2020-10-20 18:18 -0700, John Jason Jordan <johnxj at gmx.com> wrote:

> My two PCIe 3 cards got here a week ago and I mounted the four U.2
> drives on them while waiting for the case to show up. It finally made
> it today. (Fedex has put it on a truck for delivery every day since last
> Wednesday, and the driver finally decided to deliver it today.)
> 
> The case is a Magma EB3T-V3 which the vendor assured me could take the
> two Sonnet Dual Fusion PCI cards. Well, I can push them down into the
> connectors, but some of the connectors on the cards do not make
> contact. That is because the connectors in the case are about 2.25"
> long and the connectors on the cards are about 3.25" long.
> 
> I think I've been had, but I'd like some education about what kinds of
> connectors PCI cards are supposed to use. And what are the different
> connectors called? So far Duckduckgo hasn't come up with anything.
> _______________________________________________
> PLUG: https://pdxlinux.org
> PLUG mailing list
> PLUG at pdxlinux.org
> http://lists.pdxlinux.org/mailman/listinfo/plug
> 

-- 
Linh Pham