I have to disappoint you all, S7 is full of chips and cooling elements in ,what is a lethal combination.
It is hot air tornado!!. Much worst than S5.
Unfortunately inside S7 is so overcrowded with chip and cooling elements ..the method with other quieter fan does not help.
Actually, I received a replacement hash board for my S5 recently which has the many-small heat sinks, one attached to each asic chip, and it works great, and runs a LOT cooler than the old-style cooling system, where all the chips on the board have thermal paste on top of them, and they are all in contact with one large heat sink.
So I'm sure the S7 (and S5+) need far less fan power to keep them cool, which is why they can be packaged so much more densely.
-dave