AMD FirePro W9100 vs NVIDIA Quadro K6000

4K testing isn't a primary focus of this review because 4K support in these benchmarks is rare and unofficial. Nonetheless, we did run a handful of 4K tests -- mostly by tricking applications to operate in that mode. In SpecViewPerf12, it's relatively easy to force 4K but at least one benchmark (PTC Creo) won't run its scenes properly. We ran the other SpecViewPerf 12 tests in 4K -- interestingly, some of these tests consumer 4-6GB of RAM at this resolution, which implies that the 12-16GB frame buffers on top-end cards really could get a proper workout in future versions of the test.
Here's what I'd note about our 4K results in aggregate:

The W9100 closes the gap substantially against the K6000 in 4K mode. On average, the W9100 is 82% as fast as the K6000 in 1080p. In 4K, the W9100 is actually 1% faster (on average) than its Nvidia rival. The W9000 widens its lead over the Quadro 6000 as well (from 1.77x faster to 2.11x faster).  The biggest difference between the two families is the performance hit from moving the snx-02 test from 1080p to 4K. Nvidia's Quadro K6000 drops to 58% of its 1080p performance in that specific test, while the W9100 holds on to 86% of its initial performance.

It's possible that over the long term, the FirePro W9100 may have an edge in 4K workstation performance, but it's far too early to make that call -- we'd want to see a more robust set of tests actually designed for 4K screens before doing so.