I received a Gigabyte Z170-HD3 motherboard for Christmas and, among other things, it is compatible with M.2 and SATA express. After some research I still have three questions about these technologies and how they interact with my motherboard. First, can all M.2 cards interface with PCIe (and therefore benefit from higher transfer speeds), or can only some do this and others just interface with SATA3? Second, does using a M.2 slot take up my PCIe x4 slot; I ask because the two ports are not located next to one another. Last, is SATA express support for my motherboard even relevant, or did it never catch on as a product. Thanks for the help.