even the best asic now will mine peanuts for you let alone computer, you need a big farm of asic not even a single asic, but it's true that new asic are coming, i guess those new asic will be made obsolete quickly because of the halving
yeah right today an s-7 with a psu would be about 650 usd
burns 1325 watts at the wall and makes about 2.75 usd a day after power if your power is 10 cents a kwatt. or 82.50 a month
if you know how to build a cheap rig
mobo = 75 usd
windows 7 = 40 usd
cpu = 45 usd
psu = 90 usd
ram = 40 usd
dvd player = 20
ssd = 60
total = 410
2 r9 380's = 390
price = 800 power used = 400 watts
you get 40 mh for the 400 watts that is about 135 usd - 30 power
at ten cents so net is 105 a month but you have a real computer with good video cards.
you use 400 watts not 1325 watts
and you mine Eth coin not btc...... so for today right now it is an easy choice
plus