I am trying to use the i7/dGPU Surface Book using the Surface Dock with two U32D970 Samsung monitors via mini-DP to DP. Only one works at a time. Why? Using DP 1.2 cables to mini-display on the dock. I can get each one to work, but not at the same time. They said it specifically supports two 4K monitors in the presentation from Microsoft. I have recently seen other posts with the same exact issue, so I sincerely hope MS has a firmware fix for this as soon as possible? It seems that ALL ports on the new Surface Dock working with the Surface Book are not working correctly. The Surface Book device itself is great, but the dock has been a nightmare to use. I also have an issue trying to use a simple Vantec external 5.1 sound card with the new dock. I REALLY hope they have a way to fix these types of issues soon. The Surface Dock is going to tarnish the great reputation of their flagship laptop otherwise.