NVME M2 drives: which slot to use?

pciex1_1 slot   Dan arising phoenix slot

No You do not need to populate the PCI_Ex1 expansion slot What motherboard and CPU did you purchase? What graphics card and power supply did

A PCIe x1 slot has exactly one PCIe lane to use, and the same rule will generally apply moving up the ladder through x4, x8, and x16 slots Each available PCIe PCIe slots and cards A PCIe or PCI express slot is the point of connection between your PC's “peripheral components” and the motherboard

pcie slot x16 PCIe x16: This is the largest PCIe slot with 16 data lanes PCIe x16 slots are associated with graphics cards and provide the highest bandwidth available PCIeX1_1 or _2 slots As per: com GA-P67A-D3-B3 Specification Motherboard