4 btc/$560 cost basis for 10gh + starting difficulty 88,000,000 + only 15% per difficulty increase = $27 profit after 12 months. No go.
Mining is dead, long live mining!
What calculations for % gain in BTC price?
Sorry for the tangent of the thread... but I feel it's relevant.
If you spend 4BTC, and it never returns 4BTC... then who cares what USD price of BTC is?
The less than 4BTC you earn with the hardware will never be worth as much as the 4BTC spent for the hardware, no matter what the price of BTC is...