NVME M2 drives: which slot to use?

Brief Overview Of The Major Types of SSDs: m2 slot types Two types of M2 SSD m2 pcie slot 2 expansion card to add an additional Slot to your PC ATX motherboards have ample slots but if you have a small form factor mATX motherboard (usually

m2 slot mainboard Key E normally has PCIe x2, which is not as fast as PCIe x4 for other key types But still Can I attach a standard NVMe SSD to this socket?