The chips would be running at about 1070MHz. If power draw was linear (no voltage changes, which seems unlikely) the chips would be pushing almost 10W each. That's not unheard of - S5 ran 10W per chip around 400MHz and people pushed them even farther with less effective heatsinking than the S9 has.
Of course, the S5 was also about one third the heat density of an S9.
The S5 also didn't have any kind of board-level regulator. 10W per chip is looking like over 60A through the main regulator, which already runs hot at around 40A. If the board is immersion-cooled, heat wouldn't be as much of a factor as the saturation current of the main inductor. Once that level is exceeded, at any temperature, voltage stability goes whackadoo and regulator efficiency drops off.
If pushing the S9 to such levels the 1600w bitmain psu would probably need to be swapped out for something more powerful though right?
