The key point to remember with s9's is that the fans have to work against a fairly high airflow resistance cause by BM's insane mass of small heat sinks. That means they have to produce high static-pressure which is why they run high rpm. That in turn = loud.
Unless the miner is UC/UV'd there is no getting around this.
100% true....with a but...
I have many S9 units that are not 100% great.
They are really worth zip at the moment. Nobody wants old, flakey miners. By the time I ship them everyone looses money (except FedEx Ground)
However, I can put in fans that are quiet and use them as small heaters in the warehouse over the winter.
It is never going to get above 40F in there so I can run them with lower speed / lower noise fans and the miners are probably never going to care.
If they do go get to hot they shutdown. If they loop between being too hot and then 40F and this causes the hash boards to finally fail, no big loss the beagleboard is probably the only thing that is worth money.
Sad that it has come to this, but it is what it is.
-Dave
