Im selling what the customer wants, that is more mh for an acceptable price. No im not trying to sell here, just showing some work im proud of.
Offcourse you can undervolt to best mh/w ratio but thats not affordable to sell.
If by customer you mean
NOOB, someone that doesn't understand what he is buying,.. well yeah you r right

Happy
summer mining at
+85'C with those rigs, at least the PSUs wont shut off, cause there is two LoL

which in my country equals to ~20$ higher electricity bill.
Just admit that you lack the imagination and skills needed to power 6xGPUs with a single PSU that is made for 4xGPUs
without setting it on fire, and I might enlighten you how to do it.
