My little Bitcoin experience – Asic mining

Following my previous post on bitcoin I’ve start mining with ASIC to continue playing the technology. I’ve started with a small USB ASIC providing 2GH/s. This is equivalent to 200 times the power of my Xeon server and it was really easy to install, running on a Raspberry Pi to simplify the usage.

This post details this experience and gives some advices for one wanted to experience mining.

Get your ASIC

There are plenty of Asic solutions on the market but basically all are sold on second hand market like ebay, leboncoin. eventually some are on alibaba but basically finding Asics on traditional sites is complex. Actually the price of these device is growing with the bitcoin value and the margin on auctions seems to be better than the fixed price. Globally it is “funny” to see that the product you found on the auction market is sold at higher price as second hand than the official, initial, public price. When Antminer is announced 1400$ on official website the ebay price usually grow up to 2000€.

There are different generations of ASIC and different brands but more I search and more I conclude on Antminer seems to be THE provider who killed all the others. Concretely they sold hardware but they also own the largest pool in the world with about 20% of the total pool power. (source : https://blockchain.info/fr/pools)

Now the question is what can we found for what price. Basically small is not efficient, it depends if you want to make money or having fun.

Asic price & today’s gain

At this day (and this is subject to change regarding the bitcoin value). We found Asic in the following range:

  • Antminer U1/2 – USB miner 2GH/s about 60€ – 30€ / GHs
  • Antminer U3 – USB miner 63GH/s about 190€ – 3€ / GHs
  • Antminer S3+ – Ethernet miner 450GH/s about 350€ – 1,28€ / GHs – 0,4kW
  • Antminer S5 – Ethernet miner 1,15TH/s about 700€ – 1,64€ / GHs – 0,6kW
  • Antminer S7 – Ethernet miner 4,3TH/s about 1700€ – 2,53€ / GHs – 1.2kWh
  • Antminer S9 – Ethernet miner 14TH/s about 3500€ – 4€ / GHs  – 1,3KWh

This price per GHs is basically strange as the more powefull solution are in fact more expensive. The reason is also the energy used. Basically there is no big difference on global consumption when you can have 10 times more Hash / S.

Considering the running cost (power) per day per Hash rate

  • S3+ is 1,25€ / d => 0,0028 € / GHs / day
  • S5 is 1,87 € / d  => 0,0016€ / GHs / day
  • S7 is 3,75€ / d => 0,0009€ / GHs / day
  • S9 is 4,06€ /d => 0,0003€ / GHs / day

Now basically here is what you can expect as gain as this date per GHs (from http://whattomine.com website) – 1Gh/s is about 0,0028$ / day revenue.

Regarding the price above, you can expect to get some valuable result with a machine > S5, this is why the price for these machine is larger. If bitcoin stays the same level you need to pay back your Mining machine with the difference.

  • S3+ have no pay back
  • S5 get 1,38€ margin per day => 507 days
  • S7 get 8,17€ margin per day => 208 days
  • S9 get 35€ margin per day => 100 days

This will be false tomorrow : price of bitcoin is changing and number of machine sharing the same amount of bitcoin is growing. So the gain per GH/s can totally change in a direction or another. As an example let’s consider a S3 that have no payback today with help of (https://www.coinwarz.com/calculators/bitcoin-mining-calculator or http://www.mycryptobuddy.com/BitcoinMiningCalculator):

  • The calculation difficulty is growing and reducing the revenue:

– In the past 6 month the difficulty has grow up to 224%, this is making revenue per GH/s moving from 0,0028$ to 0,0013$

  • The bitcoin price is growing and making higher revenue:

– In the past 6 month bitcoin price has grow up to 717%, this is making revenue per GH/s moving from 0,0028$ to 0,021$.

Even is difficulty is growing in this scenario the profitability is growing from 0,0028$ to 0,0096$. For a S3 it is ( 4,32$ / day -1,25€ power / day ) = 1,77 € / day making the device viable.

Ok having a bitcoin reaching 136K$ is not a certain forecast and we are far away, it could also be 1K$ in 6 months. This is just to illustrate why the ASIC price is growing and obsolete hardware is actually searched by miners.

You may understand that mining is like stocks : it is speculation. Making personal assumptions and taking risk. So you have a lot of chance to loose all your investments…

Let start with ASICS

To start with ASIC I’ve got an Antminer U1 from ebay. As you can understand from previous chapter there is no return on invest and this is only for curiosity, fun and understanding. It could make sense in a Miracle looking approach as described in my previous post eventually.

This is a simple USB ASIC chip providing 2GH/s and a couple of joule to warm your home.

This stuff is equivalent to 600 Xeon core in my referential, so it provide 600 more chance to get a miracle 😉 lol.

This post about waiting for a miracle is interesting 😉

So warning said, the question is how to get started with a such equipment. You can simply plug it on a windows machine and download bfgminer to process hash like we have seen with cpu on the previous post.

Personally I installed it on a raspberry Pi as it was more simple for me. Raspbian is having a bfgminer package included so you just need to

# apt-get install bfgminer

Instead of mining Solo, I’ve tried to join a pool of miner. My choice was slush : it is one of the large pool with 10% of the overall computation power (actually 1,45EH/s = 1,450,000,000GH/s) The pool is getting bitcoin reward for your work based on the mining success of the pool and your computation power. Basically the pool mine bitcoin and share the bitcoin between all the miners. The payment is on regular basis (when it wins a mine) so you win some nano-Bitcoin per hour of work. The pool is making payment only when you reach 1 milli-Bitcoin and takes 10% for payment fee. The system is predicting me a possible first payment… in 6 months.

To be in the pool you just need to create an account, add a worker (Asic unit) and start mining with your asic. Basically the bfgminer command line is:

bfgminer -o stratum+tcp://eu.stratum.slushpool.com:3333 \
         -u username.workername -p anythings \
         -S antminer:all --set-device antminer:clock=x0881

The antminer:clock=… defines the overclocking setting and the hash rate you will produce.

Once start your raspberry will start to mine the blockchain. Nothing more complicated. You can use screen command to attach this command to a virtual screen and disconnect/reconnect from you RPI.

screen -S bitcoin bfgminer -o ...

To leave the screen use CTRL+a+d and then to re-attach the screen type

screen -r bitcoin

Enjoy !

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