ammaross :
Three PCIe 3.0 x4 M.2 slots with RAID support creates some seriously fast RAID-5 potential, but I feel many (if not most) potential RAID users would actually prefer four slots for RAID-1+0/0+1 configuration support over RAID-5 support.
Unless those 3 M.2 slots are powered by 4 lanes to a chip that provides the virtual 12 lanes. Remember, Skylake only has 20 lanes and 16 of those go to the GPU...
If there's a discrete GPU.
Wouldn't it be wonderful if Intel implemented a switch that opened access to those 16 lanes to the M.2 devices should no discrete GPU be detected? Or perhaps allowed for a manual lock of the x16 slot to x4 or x8? Wishful thinking? No. Forward thinking? Yes.
My point was that three slots is not sufficient for true power-user RAID applications because such users typically prefer the increased performance and reliability of a four-drive Hybrid RAID-1+0 array over a two-drive RAID-0 or RAID-1 array, as well as a three-drive RAID-5 array and its redundancy-related write latency.