The alpine ridge is only really there for Thunderbolt, the USB performance is great on my board with asmedia. I'm getting the constant full 100MB/s+ speed of my external drive instead of having it slow down to 60MB/s like it did with my old add in card.
WOW! That's amazing. You are first owner of a z170 I have heard from. That sounds truly encouraging.
I would like for the ASUS to have HDMI 2.0 & HDCP 2.2 for HTPC.