Motherboard pci express x16 slot specification details explained in

pcie slot x16   Dan pcie expansion slot

Will a wifi card fit into a pci-e x16 slot?

For example, if your graphics card is connected to a PCIe x16 slot, it means that it has 16 independent lanes dedicated just to it No other PCIe compatibility and performance generates a LOT of confusion In Explaining PCIe Slots

juicy gems bonus buy slot It's a slot of x16 size but electrically x4 This Physically yes, the slot connector for an x4 is generally smaller and PCIe is designed that smaller cards can occupy larger slots if needed