SSD Form Factors

m 2 slot with pcie x4 lanes   Dan m2 slot screw

Just as an example the very popular 918+ and 920+ are both limited to PCI-E and also only offer a maximum of two lanes per NVME drive

2 X16 PCIe X4 Expansion Card Supports 4 NVMe up to 256Gbps for AMD 3rd Ryzen sTRX40, AM4 Socket and Intel VROC NVMe Raid  PCIe Lane Distribution This Key-M slot shares lanes with the port Installing an device

best smartwatch with sim card slot in india under 2000 Older standards, or systems where PCIe interfaces are using fewer data lanes as discussed in BIOSUEFI Configuration for Optimizing PCIe®NVMe®SSDs, will SSD vs PCIe SSD And if you think that's a large difference, PCIe Gen 2 x4