One alternative to PCIe risers is OCuLink/SFF-8611. It lets you plug one end of a thin cable into a PCIe (or M.2) card and the other into a board with a PCIe s

One alternative to PCIe risers is OCuLink/SFF-8611. It lets you plug one end of a thin cable into a PCIe (or M.2) card and the other into a board with a PCIe slot. The main downside is that it cuts bandwidth to PCIe x4, but for most usage (e.g. LLM inference), that would be fine.