Ok, i have been doing plenty of research on these questions and i have even asked NEW EGG and SAMSUNG themselves. The way the Samsung 950 Pro 256gb / 512gb is connected is thru an m.2 slot {key M = 2280 size} on your MOBO. can not be m.2 key B nor E, those are too small or short rather. All is not lost yet, yes you can mount the Samsung 950 Pro device onto an adapter and connect it thru PCIe 4x. If your MOBO does not have a PCIe 4x slot then that same adapter can still be connected to your PCIe 16x slot {same slot as your GPU, an empty one of course} even though the slot looks a lot larger than your adapter, it's ok, it will fit. Now, you have to be sure that the adapter you get is a 3.0 x 4 with a 2280 m.2 key M connection, like this one i bought...
http://www.newegg.com/Product/Product.aspx?Item=9SIA86V3DZ5901 and you will not have any speed drop, will work at full speed. Ok, you are not out of the woods just yet, now even though you have all the right connections set up, your new SAMSUNG 950 Pro can so far only be used as a storage device...so far. Now you have to make sure that your MOBO supports NVME technology so that you can use it as a BOOT drive to load your OPERATING SYSTEM like Windows 10, 8, or 7. Just look up your MOBO model and make sure you update your BIOS because like i said, this is new tech and BIOS must be updated for support for NVME. This is very new technology and tech guys at these stores are clueless so far as to what the right connection is, sooooo, as soon as my hardware get to me via UPS, should be about Tuesday 1-5-16 afternoon, i will post up again with my success and this question can be fully answered, stamped with approval.