What is PCIe x4 Slot

For example, you can fit a PCIe x1 card in a PCIe x16 slot However, you can't do the opposite You can mount, for instance, a PCIe x1 sound

How fast is PCIe vs PCIe ? ; Unidirectional Bandwidth: PCIe vs PCIe ; PCIe Generation, x1, x4, x8, x16 ; PCIe , 1 GBs, 4 GBs

1 pg slot entrance PCIe x16 slot with faster bandwidth and lower impedance 2 PCIe Slot PCIe x4 slot with Lower impedance

1 slot In ASUS 「PCIe x16 Slots - 4」