My Surface Book is the i5/8/256/dGPU model. I've had maybe 6 DD's in the last 2 weeks and no BSOD or other weirdness...BUT... I've downloaded a few older games from Steam and they start and run very well on my SB. I have the new Surface Dock and my Samsung S32D850T 32" monitor is attached through the dock. My external speakers are plugged into the audio-out port in the back of my monitor. I get sound normally from music, videos or whatever through these speakers just fine with my SB hooked up to the dock. As long as I run a game just on my Surface Book (no dock or DP connection to the monitor), sound through the SB builtin speakers while gaming is fine. If I hook my SB to the dock to play the game using the external monitor, it appears on the monitor but no sound. I bought a new mDP to DP cable (supposed to meet all tech possibilities and demands), but still no sound. Previously, I was using the DP cable Samsung sent with the monitor and I had a DP to mDP adapter to plug it into my dock of SB. With either cable, sound plays fine to my external speakers unless I'm running a game then no game sound. I've bypassed the dock just hooking my external monitor through the mDP port on my SB - same thing. Game runs but no sound. No problems in Device Manager. I've gone into Sound controls and tested from there. Sound comes through just fine for headphones or external speakers. Oh yeah, I unplugged the external speaker cable from the back of my monitor, plugged in into my headphone jack on the SB while running the game with the monitor attached directly to the SB through the mDP port - no sound to the external speakers. Anyone run into this before, or does anyone have a good hunch what the problem is?