Supermicro proprietary PCI-E slot adapter riser cards or cables?

No, this card does use 32 actual lanes from the host X32 is in the specs, it just obviously doesn't exist on consumer boards

PCI Express slots are configured on a motherboard PCIe can scale from one to 32 separate lanes; it's usually deployed with 1, 4, 8, 12, 16 or 32

pcie 4 slot slot; x2, x4, x8, and x16 slots are also available The standard supports an x32 slot, but these are rare because of the length An x16 slot

pcie slot cover Then, it's the turn to introduce PCIe slot This slot has 7 versions: x1, x2, x4, x8, x12, x16, and x32, corresponding to 1248