What is PCIe ?

this mobo has three pci-e slots physically 1x16lanes ,2x1line What i found, the x16 slot is supporting only one pcie line according to

NVMe are pretty tiny slots for directly plugging in storage, and SATA was what came after IDE cables -PCIe tends to be

nvme m2 slot Drives that use NVMe were introduced in 2013 to attach to the Peripheral Component Interconnect Express slot directly on a motherboard

nvme m2 slot motherboard Some motherboards will only have one slot that can run at NVMe PCIe bandwidth, whereas others may be restricted to using SATA bandwidth