it's still profitable to buy Z9 or A9 ?
i have almost free electricity (0.02-0.03$ per kwh)
is it possible to achieve Payback under 4 month?
any advice?
Returns have halved every ~2-3 weeks. equihash is quickly heading towards "don't mine it", in my opinion.
Z9s still haven't shipped also.
-j
I do not think that they halved every 2-3 weeks. I started mining on one Z9 mini around June 27 and was getting ~ 0.15 ZEC/day. Now, I am getting ~0.085 ZEC/day (I am only running at 675 MHz). In other words, it did not even halved for me yet (after 2.5 months).
Look at the difficulty chart
https://www.coinwarz.com/difficulty-charts/zcash-difficulty-chartI do not see any of the dramatic drops, you are talking about. You understand that we earn less in $ because Crypto dropped a lot. What are you mining now with your GPUs? Perhaps not ETH (LOL)
I should clarify -- some of the loss is indeed in the conversion to USDT -- my accounting is done that way daily due to (annoying) US IRS regulations.
In pure ZEC, I've gone from an average of 1.6-1.9 ZEC/day (7/17/2018) to an estimate of 0.9 today (09/8/2018).
So yeah, not halving every 2-3 weeks, but a marked drop and a continuing downward slope.
I have 12 Z9 minis running currently (~192-194kSol/s pool side) and have 3 Z9s on the way (in theory, if bitmain every ships). I don't regret the 12 Z9 minis, but I'm unsure on the Z9 large units.
You referenced the difficulty chart, which as of this moment shows a 28% 1 day difficulty change, and a 58% 30 day difficulty change. While I realize there is a lot of fluctuation in the rates in a given moment, model out 60% month over month and see how fast your returns disappear. Bitmain is going to keep shipping these until people quit buying them and I expect that the units in flight over the next 30 days will at least add another 60% difficulty...
-j