With the F6 and F7 BIOS, my Gigabyte ga-x79-ud7 made clearly audible sounds. I have F8 now, and I'm going to test again with my stethoscope.
The sounds came from the two rows of black cubes in-between the CPU and the heat-pipe riser. The sounds were loudest with heavy graphics card use, but are noticeable with any significant IO load, including USB devices. The sounds are as loud as conversation, (30-60db at one meter on my sound level meter). The sounds are similar to hisses, squeals, squeaks, scratches and ticks.
My question now is if I should just RMA or return the board. I want to overclock it, but I don't expect to ever have a stable system if the power regulators are fried.