What does the X4 mean in an PCIe Gen X4 NVME drive?

Even though the PCIe 4 slot is backward compatible with the Gen 3 SSD, the fact that you're connecting it to a Gen 4 slot will not increase data

Both PCIe and slots can be configured with x1, x2, x4, x8, and x16 lanes, but PCIe slots have a higher transfer rate per lane and

pcie 4 m2 in pcie 3 slot 4 What motherboard component controls the maximum number of USB ports this motherboard could PCIe slot and a version PCIe expansion slot

pcie slot function What is the point of even buying a video card that uses PCIe if people have motherboards that only have PCIe slots?