Quote from: mechs on August 14, 2013, 12:15:09 AM

Just some math for those buying these miners. I was thinking of buying 100 USB Eruptors for .32 BTC each (so 32 BTC in all). That would require 10 hubs so assume another 2 BTC expensed there so 34 BTC on all which is now about 3400 USD.

The latest difficulty increase is in and we went from 26,160,000 to 50,810,000 in 30 days (from 7/14 to 8/13). This is a monthly increase of 194% - completely insane. This will probably continue for a few months and then drop precipitously once all these new 28nm ASICs come online in the first few months of 2014. I will be optimistic and cut this in half to a 95% increase per month assuming a huge slowdown in the difficulty increase (I do not think this will happen).

With a USB hub, 10 usb miners plus hub consume 330W/hr. I took my power costs in the US at 0.11 USD per kwh and plugged it in.

Not only will you lose money but at a 95% month over month difficulty increase, these miners will only produce 18.65 BTC (out of 34 BTC invested) in 24 weeks before becoming unprofitable to continue running. A pretty big loss.

In fact, in order to EVER break even on this investment, you have to assume the month over month difficulty increase will drop down from 194% to 30% to ever break even. A very unlikely scenario. If you do not pay for your power (live in a dorm) then the situtation only a little less bleak. You can break even if month over month difficulty increases drops to 35%. Also very unlikely.

Here is where I get my #s:

Historical Difficulty increases: http://mining.thegenesisblock.com/

95% month/month diff increase calculator: http://btcinvest.net/bitcoin-mining-profit-calculator.php?diff=50810339.048276&dcosts=3400&diff_mincrease=95&blpbtc=25&dhsmhs=33400&btcusd_mincrease=0&btcusd=100.00&dpowcon=330&dleadtime=0&pcost=0.11&calcweeks=25&action=calc

30% month/month diff increase calculator: http://btcinvest.net/bitcoin-mining-profit-calculator.php?diff=50810339.048276&dcosts=3400&diff_mincrease=30&blpbtc=25&dhsmhs=33400&btcusd_mincrease=0&btcusd=100.00&dpowcon=330&dleadtime=0&pcost=0.11&calcweeks=56&action=calc

Conclusion: Do not buy USB eruptors or the Old Blades if you wish to make a profit. Your only hope of making money mining is to pre-order some vaporware from hashfast, cointerra, or one of the other 28nm newcomers and pray they are not a scam and can deliver on time. It is much safer to simply buy ASICMiner stock than the hardware!

The numbers for a blade are no better. Only will break even if difficulty goes up to only 35% month over month at stock speed. Overclocking brings that down only a little (still over 30% difficulty to break even), since significant more power is used for cooling and overclocking (and you need to pay for a cooling unit upfront)
http://btcinvest.net/bitcoin-mining-profit-calculator.php?diff=50810339.048276&dcosts=1025&diff_mincrease=35&blpbtc=25&dhsmhs=10752&btcusd_mincrease=0&btcusd=100.00&dpowcon=75&dleadtime=0&pcost=0.11&calcweeks=100&action=calc

Profit is not the only driver for me.

Really, I can stand to lose $5-10K now playing this game. Hell, I spent more playing way dumber games Cheesy

But that's what I am doing now - converting some $USD to some virtual things. Let's say I make 50 bitcoins after spending $10,000 today, effectively losing $5,000 at today's rate. Now, what if 1 BTC becomes ONE MILLION DOLLARS (laugh), correction ONE BILLION DOLLARS (holding pinky to the lip). Obviously, I would be better of just "investing" in bitcoins today rather than in these silly blinking contraptions.

You said ASICMINER stock. OK, I got some. But are they going to survive in 12 months or not? Dividends they are paying AT THIS TIME are not making me rich. But you know what, I want to play the game. It's all about the game. In effect, without silly people like me buying into a clearly unprofitable endeavor (you got the numbers!), this whole idea of virtual currencies is going to fold. It's a self-fulfilling prophecy of a sort and is dangerously close to a pyramid. Except one thing - it may happen and people will start using bitcoins. So worst case - I lose $5,000. Best case - I make 50 billion dollars and go on a quest to conquer the Earth :O

Canary, bring more ASIC!

Again, thanks to Canary I can play better!