And a note to any developers
Don't use a few chips clocked up to the max, use lots of chips at the lowest w/GH as that's where the market needs to go.
I totally agree with this, but for the manufacturer of the chip, it's more profit to sell less chips on a board for the same price/hashrate.
And for the "independant" builders, the chips are expensive, so they need to do the same, but only to have a fair margin.
I was looking at building my custom boards, mainly for my own use.
The chips would cost me almost half the price of the finished product, and final price was similar to what is actually selling at 0.6$/GH
I had to put roughly 30% more chips on the board to reach better efficiency.
At this point, you'd better buy a finished product and undervolt it, unfortunately.