Pcie Lanes Connectx-3 NIC question

PCIe 4 is backwards compatible with gen 3, 2 & 1, and you will get at least the same performance from putting a drive in a slot as you

Hence it should be technically possible to go with a host card in x8 to achievetransport the same bandwidth for a 0 x4

can you connect pcie 40 in 30 slot Like USB, PCIe is forward compatible This means that a device which requires PCIe will work in a PCIe or PCIe slot Slot Size Lane Width

can you put pcie 4x in 16x slot PCIe Gen 3 IO Expansion Drawer with the location codes for the PCIe adapter slots in the PCIe Gen 3 6-slot 4 P1-C4 PCIe Gen 3, x16 Slot 5 P1-C5 PCIe