Becoming a major Bitcoin miner in 2018 is a bit like setting up a shoe factory; only profitable if you’re able to compete with the Chinese. Specifically, you’ll need cheaper electricity and better access to the latest mining hardware. That’s a pretty tall order, considering that several Chinese regions are over-supplied with state-subsidised power and that the country produces most of the world’s ASIC miners, usually in close partnership with Bitcoin miners.
On top of that, the mining game got even tougher following the second halving event, which reduced the reward for successfully mining a block from 25 bitcoins down to 12.5:
Daily rate of Bitcoin creation dipped from ~400 to ~200 after the 2nd halving in early July.
Chart courtesy of theTheHalvening.com.
Electricity costs will depend on your location and situation. Where Milli can help is by recommending the best available ASIC miners but first, we’ll need to explain a few technical mining terms.
Bitcoin Mining Hardware Jargon
Hashrate: the measure of how many attempts at solving a Bitcoin block a miner attempts per second. Obviously, the more attempts the greater the chance of solving the block and claiming the 12.5 BTC reward.
This figure was originally stated as H/s (hash per second). As Bitcoin mining hardware got faster and faster, SI unit prefixes were required:
- Kilohash or KH/s = thousands of H/s
- Megahash or MH/s = millions “
- Gigahash or GH/s = billions “
- Terahash or TH/s = trillions “
- Petahash or PH/s = quadrillions “
TH/s is often used to state the hashrate of current generation mining hardware. PH/s is commonly used for the combined hashrate of a major mining facility or pool, as well as the total hashrate of the entire Bitcoin network (currently at a staggering 1665 PH/s).
Joule per Gigahash: A Joule is a measure of energy, representing 1 watt over 1 second. The fewer Joules used to produce a Gigahash, the higher an ASIC miner’s electrical efficiency. As electricity is the major recurring expense of miners, this stat (often abbreviated as J/GH) is of prime importance when comparing miners.
Difficulty: with hashrate ramping up since Bitcoin’s release, one could be forgiven for expecting that blocks would be solved increasingly quickly. Difficulty is an automatic control measure which prevents that from occurring. Every two weeks, difficulty adjusts to the current hashrate so that blocks continue to be solved every 10 minutes (on average).
Profitability: this bottom-line number is calculated from the current Bitcoin price and Difficulty, your miner’s cost and hashrate and your electrical cost in fiat money per kWh. This ever-adjusting Difficulty mechanism, combined with Bitcoin’s volatile price, make calculating the future profitability of Bitcoin mining very tricky!
99Bitcoins’ mining profitability calculator is good for this purpose but if you’re serious about getting into mining, it’s recommended that you create a custom spreadsheet with inputs reflective of various exchange rate and Difficulty projections. Remember to account for probable downtime due to power cuts, hardware or software failures and the like.
Break-even point is the length of time it takes for your miner to pay for itself, if it ever does.
Pool Fees: given a total network hashrate in the thousands of Petahash, unless you control several PH/s your odds of successfully solo-mining a block are virtually nil. Mining pools are cooperative groups which combine their hash-power and distribute any rewards which the pool earns proportional to individual hashrates. Pools have different fees and reward structures which be compared here. The larger the pool, the more regular returns can be expected.
The current distribution of hashrate among mining pools, courtesy of Blockchain.info.
Bitcoin mining hardware – the top 3
Now that you understand the basic metrics used to assess Bitcoin mining hardware, here’s a comparison of the leading mining devices:
|Avalon6||AntMiner S7||AntMiner S9|
|Hashrate1||3.5 TH/s||4.73 TH/s||11.8 – 14 TH/s|
|Power Usage2||1050 Watts||1350 Watts||1350 Watts|
|Power Efficiency2||0.29 Joule per GH||0.25 Joule per GH||0.1 Joule per GH|
|Noise @ 4ft/1.2m2||55 dB||62 dB||70 dB|
|Price New2,3||$550 (Canaan)||$440 (Bitmain)||$1831 – 2016 (Bitmain)|
|Price Used2,3||$360 – $875||$440 – $674||n/a|
|Break-even point5||7 years||2.6 years||0.9 years|
1 figures are approximate and may vary by 5%.
2 figures are approximate and may vary by 10%.
3 shipping not included!
4 assuming an electricity cost of 10c (US) per kW/h, a 2.5% pool fee and the Bitcoin price at the time of writing ($680 on the 17th July 2016).
5 as per CoinWarz’s calculator and points 3 and 4.
1) The Clear Winner: Bitmain’s AntMiner S9
The table results speak for themselves!
Although the S9 is four or five times more expensive than its rivals, it also mines about three to four times more bitcoins and also uses electricity far more efficiently. If your intention is to mine for profit at a small scale, at this stage the S9 represents your best shot at success. If you’re not out for profit and you’d rather mine for hobby or experimentation purposes then the S9’s hefty price tag is hard to justify.
Bitmain is currently the leading manufacturer of publically-available ASIC hardware. Their latest model, the S9, is the first ASIC to market with a 16 Nanometer (nm) semiconductor fabrication process. In layman’s terms, this means that the circuits in the S9’s BM1387 chips are nearly half the size of previous generation mining chips. This results in far greater electrical efficiency – less J/GH! – putting the S9 at the forefront of mining tech.
While other companies are developing 14nm chips, smaller fabrication processes are costly and time-consuming to establish. This means that the rate of advancement in Bitcoin mining hardware, remarkable for its speed and for being funded without major corporate involvement, will inevitably slow in the years ahead until the limits of current semi-conductor technology are reached. This means the S9 should be fairly durable for the new two or three, unless some other optimisations are developed.
Nonetheless, it’s highly unlikely that break-even will be reached in less than a year as the overly-optimistic calculator suggests. However, with cheap enough electricity, the S9 should eventually pay for itself. As more miners upgrade to the S9 (and other hardware yet to be released), Difficulty should be expected to rise. Such Difficulty increases will extend the break-even period significantly but probably not beyond 2 years…
Note that the S9’s performance varies considerably according to production batches. The initial release achieved a hashrate of 14 TH/s but currently available units achieve only 11.85 11 TH/s. As the power consumption of new models is also lower, efficiency remains similar.
The S9 will run on a standard PSU but Antminer’s 1600W APW3-12-1600-B2 is often recommended. It’s designed specifically for mining and available for an additional $140 (plus shipping), which is a pretty good deal considering its high quality.
S9 with APW3 PSU.
- Best available hashrate of 14 TH/s (early batches) to 11.85 TH/s (current batches)
- Extremely power-efficient at roughly 0.1 Joule per GH/s
- Works off any regular PSU (power supply unit) rated for or above 1350W
- Expensive at around $2000 (plus shipping) for the current batch
- Not yet available as used
- Too noisy to run near to people in a home or office
2) The Runner Up: Bitmain’s AntMiner S7
The S7 is still the most commonly found hardware in any major mining operation. In fact, it’s so popular that you’ll struggle to find a good used unit at a price cheaper than new! Of course, it can still be worthwhile to buy an S7 second-hand if it’s available locally, to save on shipping time and costs.
The S7 is in demand for a reason; it offers close to the maximum efficiency which can be squeezed out of a 28nm process, although it can be improved further through skilled modification. The S7 also has a more affordable price tag than the S9, making it an easy introduction model for prospective miners. If you want to experiment with alternative energy solutions or hardware and software mods, the S7 is a great test-bed which can also turn a profit – or at least not lose too much money.
S7 from Batch 18 with dual fans
The S7 is also available as a variant model, the S7-LN model, featuring a built-in 700W power supply. Less power means fewer hashes and the LN only achieves 2.7 TH/s. On the plus side, less power also means a lower price of around $291 plus less heat and noise. The LN is good for home or office use, although you’d probably want it behind a closed door. Note that the weight of the attached PSU adds considerably to shipping costs.
- Good hashrate of 73
- Decent efficiency of 25 Joule per GH/s
- Relatively inexpensive at $440 new (plus shipping)
- Widespread hardware means a lot of available information and spare parts
- Overshadowed by 16nm miner and soon-to-be-released 14nm miners
- Uses a lot of power at ~1350 Watts, which requires a high-end PSU
- Produces considerable noise at 62dB (although the LN is quieter)
- Hard to find second-hand
3) The Underdog: Canaan’s Avalon6
Given Bitcoin’s decentralized ideals, many are unhappy with Bitmain’s dominance of the hardware market. As Bitmain also controls 18% of network hashrate in the form of AntPool, such concerns are understandable. Unfortunately for those who’d prefer to avoid Bitmain, there isn’t an abundance of suitable alternatives at this time.
The Avalon6 from Canaan Creative is probably the best option. Although it doesn’t offer quite as much bang for the buck as an S7, it’s still a very good 28nm miner. The Avalon6 achieves a slightly lower hashrate and efficiency but uses about 300W less power. A smaller and cheaper PSU can be used.
Offsetting any PSU saving is the fact that the Avalon6 doesn’t with an inbuilt controller. It’ll need to be run from a Raspberry Pi (B, B+ or RPi2). The good news is that a single RasPi can run up to 50 units.
- Achieves a decent hashrate of 5 TH/s
- Reasonably efficient at 29 W/GH
- Small form factor and quiet fan
- Canaan has a distributor in the US for fast and inexpensive shipping
- Avalon6 units need a separate controller
- Pricier than the S7
- Lower efficiency than the S7
This article describes the current state of play but new technology gets released all the time. Some promised chips with the potential to challenge the mighty S9 include the following Bitfury’s as-yet publically unavailable 16nm BF8162C16 chip and BW’s 14nm chip, scheduled for release in “winter 2016.”