Since I stole your build and we built virtually the same computer, it is crazy that I see you posted this. Not quite the same thing, but close.
A day or two after completing the build, I was playing the free Doom we got just to test things out, and all of a sudden there is this horrendous clacking noise. I quickly determine that it is from the video card, and the brace was pushing on the card so that one of the fans was hitting the front bezel or whatever you want to call it. Still spinning, but a godawful racket, and I'm sure not good for the fan at all. I just pushed the brace a tiny bit over and it fixed it, but between yours and mine it seems like that fan is incredibly touchy. I'll have to watch out for it, because with it facing down I doubt I'd ever even notice if it weren't spinning unless it made a noise.