Quote from: Master One on August 28, 2014, 07:31:32 AM

Well, I have been playing with the idea for two weeks now, and I have come to the conclusion that I really have to write off the idea to start mining with either a bunch of S3+ or two SP31, as it's just not worth it.

Even when calculating energy costs with only 0.0921 $/kWh (which is an unrealistic value for me here, that I could only achieve with a little trickery) and a difficulty increase of just 20% per month they are not going to reach a positive ROI or turn negative just when reaching.

And yes, it's not only about reaching a positive ROI, but to make a profit as well. If you buy a S3+ for BTC0.58 it has to mine BTC0.58+ independently of a rising BTC value, because otherwise it would have made more sense to just buy BTC (considering to become a hodler).

We have to face it, with a total network speed of more than 200 PH/s at the current difficulty, increasing with such rates the 28nm ASIC technology has to be considered as obsolete, as it's just not possible to squeeze it at less then 0.5455 W/GH (at the wall; that value is for the SP31, with the S3+ it's 0.7837 W/GH or overclocked 0.8 W/GH). Energy is not going to get cheaper neither, so we really need new hardware.

The hardware manufacturers currently are not able to keep up with the increasing difficulty, and without a miracle it pretty much means the end of private mining. This may seem pessimistic and there may be new opportunities with tech <20nm but it really depends on the manufacturers' strategies, because if it stays the norm to keep customers waiting while mining the hell out of new units themselves till difficulty kills the opportunity for the customer to reach a positive ROI again, nothing is going to change.

I really was that close to hit the order button on a couple of S3+, but now I'm just going to watch the BTC value, buy a few BTC for hodling when it feels right, and wait for new hardware to be announced (which most likely is not going to happen this year).

Good luck to you all, especially to those who are as late to the game as I am and didn't do the math.

I know the feeling. I was also debating buying S3s but now holding to see what happens. I'm still mining with 8 S1s and they're down to pulling in about 1 BTC a month. At my electricity cost of $0.13/kWh this cost me about $340/month. So I'm still making a small profit at the current BTC price. May upgrade using the kits, but not worth it yet. Waiting to see what happens.