This is what I wrote earlier, but no one replied with numbers. I don't feel like a lot of people here have done the math.
But isn't the s7 maintenance cost more than double of the s9? Can someone show a screenshot of s7 and s9 earnings and maintenance cost?
When I run it through bitcoinwisdom mining calculator, they are both unprofitable over time but the s9 is closer to breaking even.
https://supload.com/rJL7uGurlAs far as I can tell neither will earn money more than what you spent. After spending some more time looking at how much maint the S7 is, I see some large maintenance charges added every so often. Whereas before maintenance was working out to 20% of the payout for S7. Now with these large charges its 50% of the payout, so S7 doesn't look as attractive as it did before, but its still better to buy S7 over S9 based on the price/hash difference.
I notice that prices have gone up in the last 24 horus. Is this because of the BTC continuing drop?