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

What does the X4 mean in an PCIe Gen X4 NVME drive? nvme m 2 slot Similar to the SATA SSD, the NVMe SSD utilizes the same compact form factor but an NVMe PCIe interface for data transfer NVMe SSDs offer nvme pcie slot Supports AMD Socket AM5 Ryzen™ 9000, 8000 and 7000 Series Processors; 8+2+1 Power Phase, ; 2 x DDR5 DIMMs, Supports Dual Channel, up to 7200+ ;

nvme pcie slot NVMe SSD 50% slower on socket 1

nvme slot The adapter card I am looking at can be used in a X4, X8 or X16 PCIe slot and they say I will get up to 32Gbps when it is plugged into a PCIe This video explains how to select which slot to use on a motherboard for the best storage