I couldn't boot 1866 or 2000. I was able to load the 1600 CL7-7-7 1.9v XMP profile but I dropped one channel. It shows both modules installed in BIOS but 1024MB on POST and 1GB in task manager. Windows sees 2GB but apparently "1GB usable".
EDIT:
After changing slots to the black ones on the Crosshair V Formula I was able to boot at 1800 7-7-6-18 1T @ 1.95v with both sticks.

