First time posting a build here! Howdy from /r/buildapc :)
This build was actually an "upgrade" build. I previously had some of these parts inside a Raven RVZ02 with a 980Ti. With the announcement of the 1080, I decided I'd go with a custom watercooling loop in a Define Nano S, to keep the 1080 cool, and to add a little excitement into my life.
Initially, I had planned to use 2x240mm radiators for this build, BUT THE MAXIMUMS VIII'S VRM RISER DOES NOT ALLOW YOU TO FIT A 240MM RADIATOR ON THE TOP. With that, I decided to default back to a handy 120mm radiator for added cooling, and mounted it to the rear fan area. It works well.
Other than that, everything JUST fits. The 750W EVGA SuprNova P2 is on the longer side by 5mm, but I found there to be enough clearance with the D5 pump. I tried a number of tubing configurations before landing on this one. If I had unlimited amounts and types of fittings at my disposal I might have done a couple of things differently, but I tried to keep it as clean as possible. The extended fan controller that came with the MAXIMUS VIII mounts perfectly on two screw holes found on the rear 3.5" drive bracket, making for a convenient mounting point.
Overall, this computer runs insanely silent at idle and silent at gaming loads, with my Noctua fans spinning at ~1k RPM and the Prolimatechs around 1100pm for added airflow. My configuration has the front fans pushing air through the rads, the read fan pulling air through the radiator out, and the top fans blowing air in.
So far, I have reached ~2088mhz boost overclock on the 1080, at a stable 46-48 degrees Celsius during load (2 hours of Overwatch, multiple runs of Firestrike) and 28-31 C at idle.
Not sure what else to say, other than I'm happy with how the build turned out. I have historically been against the "red and black" look, but I decided it would be a challenge to make it work in a way that I enjoyed it, and that's what I did here. Feel free to ask any questions below!