NVMe vs vs SATA vs PCIe: What are these SSDs?

What does the X4 mean in an PCIe Gen X4 NVME drive? 2x m 2 ssd slot nvme pcie gen4 is a slot that can interface with SATA , PCI Express 2xbet slot 2 X16 GEN 4 CARD , which allows you to extend with four extra NVMe's The issue however, is that it only runs four of them, when

2x m2 ssd slot nvme pcie gen4 Crucial NVME PCIE SSDs unlock the performance of your computer and deliver shorter load times and faster data transfers