The protocol tries to generate 50,400 bitcoins for every difficulty change. For the next difficulty the network will be about 60,000 GHashes/sec. My avalon will be about 65 Ghashes/sec. Thus I will get 65/60,000 * 50,400 bitcoins = 54.6 bitcoins. Thus, my spreadsheet above is wrong. If the network grows 20% durring the next difficulty I will only get 80% * 54.6 = 44 bbitcoins. Still alot more than I said this morning.
44 bitcoins is a lot. But I need to make 108 to recover what I spent on the thing.
I will try to figure this out again when I get home tonight.
Sam
I can guarantee that you will get a ROI in much much less than you expect.
No need to play with spreadsheets, just use:
http://www.bitcoinx.com/profit/You will see that even with a x10 difficulty increase during the next 12 months (0.1 in the "profitability yearly decline" variable) and with less than 90% uptime (60GHs instead of 68GHs), your machine will ROI in BTC in aprox.
30 daysFor batch 3 customer this looks different:
20 million starting difficulty
650 watt
cost of mining machine 8000$
0.1 profitabilty yearly decline
60ghash
66days to break even
12k first 12 month profit
if the price is stable at 100$ next 12month.
thats a massive bummer, considering that #2 customers will make a killing. if you get your batch 3 order early you might get faster break even, but not in terms of bitcoins, only in terms of money. in that case, not buying batch 3 would have been more intelligent.
I do not know what kind of amazing investments you do with your fiat, but a 66 days ROI is amazing. Even a 180 days ROI is acceptable as far as I'm concerned.
Then, I do not really care about USD profit estimations. First, because it is too much of a gamble. Secondly (and more important), because I bought a mining machine in BTC to generate BTC while supporting the network. As long as electricity gets paid, I really don't care about BTC/USD.