The 17 R3 only has 2 M.2 slots. If the Alienware 17 that you have has 4 M.2 slots it's either the R2 or an M17! And if it's either of those laptops, The 950 Pro and SM951 would be a waste of your money as the M.2 slots are SATA whereas those drives are PCIe. Further, if you do have the 2015 17...