Friedcat: Would it be possible to give a power estimate in Wattage per GH
BFL and Avalon came out with theirs so it would be good to be able to compare, I know you gave yours in Joule/GH, but there's no way to compare the 2 without having more info
Thanks
Our spec is 4.2 (Watt / (GHash / s)). Because 1 Watt = 1 Joule / s, it equals to 4.2 Joule / GHash.
We know that:
1 kWh = 3,600,000 Joule
1 GHash = 50 / (4 * difficulty) BTC [before block reward halving] or 25 / (4 * difficulty) [after block reward halving] BTC
Suppose the price of electricity per kWh is pe, and the price of BTC is pb, the difficulty when we are un-profitable any more is d, we have:
4.2 * pe / 3,600,000 = pb * 50 / (4 * d) [before block reward halving]
or
4.2 * pe / 3,600,000 = pb * 25 / (4 * d) [after block reward halving]
therefore:
d = (3,600,000 * pb * 50) / (4.2 * pe * 4) [before block reward halving]
or
d = (3,600,000 * pb * 25) / (4.2 * pe * 4) [after block reward halving]
First we could fill in the (pe) field [0.1$ in China]. Then we could speculate on the average price of Bitcoin during the whole operating time and fill in the (pb) field to get the average difficulty cap, below which the miners could have non-negative margin profits if they consider electricity cost to be their only margin cost.
