Meet The NVIDIA Quadro M6000
At first glance, the M6000 may seem like a fairly small upgrade compared to NVIDIA's previous top-end GPU, the K6000. Both the older GPU and the newer one have 12GB of RAM, 384-bit memory buses, and roughly similar numbers of cores (the K6000 had 2880 GPU cores compared to 3072 on the newer M6000). The memory clock is slightly higher, at 6.6Gbps, up from 6Gbps, but the on-paper advantages of the M6000 over the K6000 are fairly small.
Find the new NVIDIA Quadro M6000 On Amazon, when available...
NVIDIA's documentation indicates that the M6000 supports DX12 Hardware Feature Level 12_1, whereas previous GPUs from the Kepler family only support DX12 Feature Level 11_0. Both GPUs will work under DX12, in other words, but certain advanced features of the API will only be available on the M6000.
AMD's competitive offering
AMD retains the same display output advantage over NVIDIA, therefore, that it had last year. If you need to drive six 4K displays off a single GPU, or you have a GPU-specific workload that requires up to 16GB of frame buffer memory, then the W9100 is your only option on the market today. The M6000 does chip away at one of these advantages -- it offers 4x DisplayPort 1.2 ports, compared to the K6000's two.
The W9100's ace in the hole may be its overall price/performance ratio. While it wasn't as fast as the K6000 in all tests, AMD's highest-end workstation GPU came in a hair over $3000, significantly cheaper than the $5000 price tag of the Quadro M6000, though 12GB K6000s can be had for $3950 currently - which speaks to possibly lower street pricing likewise down the road for the M6000 as well.