This board is definitely on my shopping list.
All of you worried about the M.2 slot being PCIe 2.0 x2 need to be a little more circumspect. Yes, it's limited to ~800MB/s but what does that mean to you in the real world? Do you have an equally fast SSD or large enough DDR3 RAM drive to copy large files to/from, in order to hit that bottleneck? Are you involved in digital content creation?
If the answer is yes
, you have every right to be concerned, otherwise let it go - you won't see a difference anyway; certainly not while playing games, that's for sure. Me? If I could get my hands on a 1TB M.2 SSD I'd slap one in this board and call it a day - as an OS drive, 800MB/s means absolutely nothing to me. IOPS
means a hell of a lot more.
Also, taken from here
...while the M.2 slots can use either two 2.0 lanes from the chipset itself, or up to four 3.0 lanes taken directly from the processor.
The ASUS philosophy appears to be that since this is marketed as a workstation
board, it will be the core of systems intended for digital content creation such as producing 4K video. With that in mind, it won't matter that the M.2 slot is PCIe 2.0 x2 because people in that field will likely opt for a slot-based NVMe SSD anyway like the Intel 750, as well as a single graphics card. However, in the absence of an mATX X99 ROG board, this board can still do tri-SLI with the M.2 slot occupied (and a CPU with enough lanes to make it worthwhile) - at least it appears so.