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

pcie nvme slot   Dan pcie slot pinout

SSD into the expansion slot PCI-Express Gen4x4 supported NVMe SSD Storage space, 250 GB

An NVMe drive is also an SSD Instead of connecting it via a SATA III cable, it plugs directly into the motherboard via the PCIe slot or into a traditional expansion slot is the specification for internal expansion cards on computers' motherboards Intel first introduced slot in 2012 as

pp4d slot PCIe, is a standard interface used for connecting high-speed motherboard components while NVMe is the communication protocol or interface nvme Toshiba XG3 512gb connected to the bottom most nvme slot HDD activity 2_2 socket shares SATA_56 ports when use PCIE mode device in X4 mode