pci e slot types: Supermicro SYS-621C-TN12R CloudDC 2U Barebone .... USB Isa | eBay. 1 x pci e x16 slot - ayofa.vn.
Up to 6 PCI-E Gen 4 x16 (4 internal, 2 external)
slots, 1 PCI-E 4.0 x8 AIOM
slot M.2 Interface: 2 PCI-E 4.0 x4.
Slot types varied between models some being all with one 4x slot or others a desktop riser card with one and
PCI slot and two shared PCI-ISA slots.
Product - 12-slot [PCI-E x16 (1), PCI-E x8 (1, x4 signal), PCI (9)] PICMG 1.3 Industrial Backplane.