There was a huge drop on price for S7 in the last 24 hours or so , do we know the reason for it?
Next diff change will be about 20% which will practically mean the S7 will not survive halving at current BTC/USD price, in other words it will never ROI.
this is assuming the diff will stay the same, which is very unlikely.
halving will bring diff down, or everybody will mine at a loss.