Printed a fan bracket and stuck a foam gasket on top.
Prime95:
No Fan Duct: 93 °C
Fan Duct: 89 °C
PCH, M.2, and memory temps dropped by 3-4 °C. Ambient: 22 °C.
i7-7700K Delidded, 5.0 GHz, 1.312 V, LP53 + NF-A9x14 + no I/O shield.
More testing to do, thought I'd share.
That is a gorgeous system. Now plug in front panel headers and Sata cables.
I have to say, I'm awfully impressed with how large a difference having a fan duct of some sort has been making for people; that's an easy fix to pick up 4-5 degrees. Was it tricky to make?