what does wired mean in 'one PCIe x16 wired x4'

PCIe x4 devices are compatible with larger PCIe slots such as x8 and x16, and can be installed in these slots as well However, the bandwidth of the device is

PCIe cards can always operate in PCIe slots with the same or more lanes than the card For example, an x8 card can operate in a slot with x8, x16, or x32 lanes

can you use ddr3 in ddr4 slot PCIe x16 slot with faster bandwidth and lower impedance 2 PCIe Slot PCIe x4 slot with Lower impedance can maintain its performance

candyfinity slot If the PCIe slot has x16 mechanical and x8 electrical, you can have 16 cards, but performance gets halved due to half the lanes That is how you can fit a PCIe