Success - Sierra + Kaby Lake i7 7700k + ASRock Z270 Extreme 4 + G.Skill 32GB ddr4-2400 + GTX 980

[Delphius]

Ok, good news! My Asrock TB3 AIC is working well, after CMOS reset and changing BIOS settings. The manuals don't provide much information about Thunderbolt BIOS settings, and I think the "TBT Host Router" setting was the clincher. It defaults to "Two ports" but after the CMOS reset, "One port" got it going. My LaCie d2 TB2 hard drive shows up in System Report as SATA, but I'm not sure what speed it is working at.

Thats great news! Thanks for keeping us informed about the status. This will be very useful in the future.

 

[Delphius]

Still having the same randomly restarts: when I browse for pictures in Finder usually when I try to preview them, when I boot back from Windows it restarts within 5 seconds and then it works normal or today even when it got back from wake

I'm not totally sure what could be going on with this. Maybe something unrelated to GPU? It might be unique to your motherboard or there is something wrong in the patches.