When one thinks of an M.2 SSD, we typically associate that with either a SATA 6GB/s or more recently with a PCIe 3.0 x4 link. The physical interface of M.2 was meant to accommodate future methods of connectivity, but it's easy to overlook the ability to revert back to something like a PCIe 3.0 x2 link. Why take a seemingly backward step on the interface of an SSD? Several reasons actually. Halving the number of lanes makes for a simpler SSD controller design, which lowers cost. Power savings are also a factor, as driving a given twisted pair lane at PCIe 3.0 speeds draws measurable current from the host and therefore adds to the heat production of the SSD controller. We recently saw that a PCIe 3.0 x2 can still turn in respectable performance despite lower bandwidth interface, but how far can we get the price down when pairing that host link with some NAND flash?
Any major computer upgrade generally requires a full software reinstall too. No so if you heed the advice in the guide to Upgrading a Motherboard without Reinstalling. PCSTATS Tips