Bitmain Antminer S9i Review: Legends Never Die

When the Antminer S9 came out in 2016, it gave a big shock to the mining industry. It was way better than the previous generation, and this helped miners stay profitable for a long time. It's still used to this day to mine bitcoins and keep their house warm at the same time. It's literally become the symbol of a whole generation of miners and bitcoiners.

The Antminer S9 was way ahead of its time. It was almost 200% more efficient than the previous model, the Antminer S7. That's amazing because it could do a lot more TH/s by using the same power: 14 TH/s while using a maximum of 1380 watts. It looked just like the older version, the S7. This was possible because it used a new kind 16nm chip called the BM 1387 ASIC, which made it extremely efficient. With this miner and its stock firmware, it takes approximately 98.57 watts to produce 1 terahash.

But the Antminer S9 can be even more efficient. With aftermarket firmwares like Braiins OS +, it can do even better numbers. In this review, I'm going to test an updated version called the Antminer S9i. It's basically the same as the S9 but a bit cheaper and released two years later as an update version. Luckily, I found a brand-new one from 2018 that had never been used, the box came unopened, just like a time capsule. It came from a company that went out of business before they could use all the machines they bought. Let's get started!

👉 Click here to get the Bitmain Antminer S9 on D-Central for a special price.

Bitmain Antminer S9i: What It Is?

The Antminer S9i is a SHA256 miner, which means it can mine major coins like Bitcoin. You just need to plug it in, connect it to a mining pool, and start mining. When blocks are found, you'll get your coins sent to your specified address. It's an easy way to earn passive income. However, since this miner was released nearly a decade ago, it's not as efficient as the latest models. Mining is highly competitive, and older machines like the S9i can become outdated quickly.

So, is the Antminer S9i obsolete today? The answer is: it depends. If you have free electricity, it can still help you earn some Bitcoin every day. But if you have to pay regular electricity rates, its efficiency might not make it profitable anymore.

For this reason, in the recent years, the community has repurposed the S9i as a space heater that also mines Bitcoin. It's very cheap to buy, which makes it a popular choice for this dual purpose. While it heats your home, it also earns you some Bitcoin.

For comparison, a newer model like the S19 has 95 TH/s of hashing power, 34.2 J/TH efficiency, and costs around $1000. The S9i, on the other hand, has 14 TH/s of hashing power and 98.2 J/TH efficiency, making it less powerful and less efficient. However, the S9i costs is sometimes under $100, including the power supply, which is much cheaper than the S19. The S9 has also a very low power consumption: just 1375 W, while newer models usually use around 3250 W at the wall.

This low cost makes the S9i a favorite for home heating while mining Bitcoin. With nearly 200 BM1387 chips, it generates a good amount of heat. Plus, with aftermarket firmware like Braiins OS+, you can reduce power consumption and noise, and even improve efficiency. More details on that later.

Bitmain Antminer S9i Main Features

The Antminer S9i is an industrial miner in every part of it. Even if it's not excessively heavy, it's not your typical sweet device with great design you might see in an Apple Store. This is more like a machine than a device, because it's work is not looking pleasant but be efficient and hash the highest amount while consuming the lowest possible, being good value for money, and also staying cool.

14 TH/s hashing power

It's not much, but it's honest work. Ok, let's be real: 14 TH/s is really nothing in a 5th epoch world. The S9i it's extremely inefficient also that it makes it a non-viable choice for any miner that is doing it for business, for example in a mining farm. However, the S9i has all the characteristic to be a great choice for a hobbyist miner or every person that would like to heat their home, while at the same time hashing with a power that is superior with the other home mining solutions like the Bitaxes or the Avalon Nano 3. The S9i is still the king in hashing power and quick for space heating a room, or even a house.

A Great Space Heater

The S9i is great at being a space heater. Its rectangular box shape has a cooling system where fans push air through the device. The front fan pulls in cold air from the room, which then passes over (very big) heatsinks inside the device, heated by the chips' work. The back fan then blows the hot air out. This heat can be used for various things, like heating your house, but also greenhouses, indoor farms, aquaculture systems, and fish farms.

Industries can use the heat for manufacturing or drying, cutting down on energy costs. Also, mining heat can be added to district heating systems to provide cheap and sustainable heat for communities.

There are many DIY mods for the S9i, often using 3D printing. For example, Crypto Cloaks makes a Bitcoin Space Heater DIY Case. There's also a company called Heatbit that uses the S9 as the core of an air purifier/heater in a stylish shell.

Antminer S9i Features

What makes the Antminer S9i a good choice for home miners? Let's look at the main reasons:

• Affordability: New units can cost around $100-300, but used ones on eBay are around for even less with the power supply included. It's an affordable option for beginners.
• Hashing Power: It offers 14 terahashes per second (TH/s). While not the fastest, it's a solid starting point. Just make sure to check your power bill to see if it’s cost-effective for you.
• Power Consumption: It uses up to 1375 watts, similar to a small oven at max power.
• Form Factor: The S9i is bulky and heavy because the power supply isn’t integrated. If space is limited, finding a safe spot for it might be challenging.
• Connectivity: It doesn’t have built-in Wi-Fi, so you need to connect it to an Ethernet cable. However, you can buy a VONETS VAP11G-300 to convert Wi-Fi to Ethernet and place the miner anywhere in your house.
• Compatibility: It can mine cryptocurrencies using the SHA-256 algorithm, like Bitcoin, and can connect to any pool that supports Stratum V1. You can also install aftermarket firmware like BraiinsOS+ via the MicroSD slot to underclock/overclock, improve efficiency, and reduce noise. This gives you many options for mining.

Bitmain Antminer S9i Quick Review

Here's a quick overview of the S9i. We've examined its main features and evaluated its investment potential. If you're short on time, check out the table below.

One key factor to consider is its energy efficiency. While the economic efficiency (price per terahash) is quite good, its low efficiency (J/TH) makes it less efficient compared to modern miners.

However, the low entry cost makes this miner a great short-term investment and an excellent solution for heating your home—if you live in very cold places. Otherwise, you may need to turn off the miner or use insulated hoses to expel the hot air when the weather is warmer, as this miner generates a lot of heat.

Bitmain Antminer S9i Unboxing

I received this brand new unit, still unopened, which was made in 2018. It's completely new in the original factory box and has never been used. It comes from a company that bought thousands of these in 2018 but went bankrupt before they could use them. So, they had many units totally new and unopened, just like this one, even stored in the original unopened pallet from Bitmain.

The box is a typical Antminer box from Bitmain. It's a bit heavy because it cointains both the miner and the PSU.

On the side of the box you can find the miner model and the serial number.

You'll find a quick instruction sheet right after opening the box. There is also a return policy (no returns accepted) and warranty info, which is for 90 days starting from the shipping date.

The S9i is well protected with an outer shell to protect during transport and a pluriball. The device arrived intact without any damage.

The device is totally new, doesn't even have any scratch, as advertised. It comes with all the hash boards, fans and control boards already installed. The only thing you need to do is connecting the hash boards. Let's unbox also the PSU.

The power supply unit (PSU) is the APW3++, designed for the AntMiner S9 but compatible with models like L3+, T9, and D3. It has ten 6-pin PCIe connectors and provides a maximum output of 1200W at 110v-120v or 1600W at 220v-240v.

The downside of this PSU is that it's not integrated like newer models. It's bulky and needs to be kept close to the miner because the connectors are very short. The fan is also very noisy, so after a few days, I replaced the stock fan with a quieter Noctua NF-A6x25 60MM FLX SSO and a CRJ 3-pin computer fan to 2-pin PSU adapter.

The power cord is not included. You will need a standard PC power cable (C13), which you can buy at a local store or on Amazon.

How To Start Mining With The Bitmain Antminer S9i

After finding a power cable and connecting the device to the internet with an Ethernet cable, connect all ten 6-pin PCIe connectors from the PSU to the control board. Nine connectors go to the hashing boards, and one goes to the fans, so make sure you connect them all.

When you plug to the power Bitmain Antminer S9i (there isn't an on/off switch) and the internet, you'll need to find its IP address on your network. Then, enter it into your web browser to access the admin panel (username: root, password: root).

The stock firmware of the S9i is pretty basic and doesn't offer many configuration options. It always runs at max power, making it extremely loud. This isn't ideal, especially if you plan to run your Antminer at home.

However, there are several aftermarket firmwares for the S9i that you can install directly from a SD card. Just change one jumper on the control board, flash the firmware onto an SD card smaller than 8GB, and you'll have a much more advanced firmware than the stock one.

I installed Braiins OS+, which lets you autotune the miner to run at a specific wattage or hashing power. During my test, I set it to autotune at 850 watts and was able to mine at 11 TH/s with very quiet fans (around 2200/2300 RPM) at a temperature of 89 degrees Celsius. As you can see, the efficiency improves significantly—from a stock efficiency of 98.2 J/TH to 76 J/TH with Braiins OS+ at 850 watts, a 22% gain!

Braiins OS+ is also more user-friendly and visually appealing. It's easy to configure, too. From the main dashboard, just click on "Edit pools," enter the URL, worker, and password, and you'll start mining in a few seconds.

Antminer S9i Design

The Antminer S9i has a rectangular box shape, like a brick. It's designed to be sturdy and practical, but not very compact. The power supply unit (PSU) is not built into the miner, so you need to keep it close by because the connectors are short.

The cooling system uses forced airflow. This means there are fans that push air through the miner to keep it cool. The front fan pulls in cool air from the room, and it passes over the hot components inside. The back fan then pushes the hot air out. This design helps keep the miner from overheating but makes it quite noisy. The densely packed heatsinks of the S9i require high static pressure for efficient cooling.

The stock firmware doesn't have many options and runs the miner and fans at full power all the time, which can be very loud and not ideal for home use. However, you can install better firmware like Braiins OS+ that allows you to control the power and fan speed, making the miner quieter and more efficient.

Overall, the Antminer S9i's design is robust and functional, but not the most convenient for home use without some modifications.

Antminer S9i Alternatives

The S9i is an industrial miner that's recently been repurposed by the community as a home miner. There aren't really alternatives at the same price, but if you are planning to splurge a bit more for home miners you should check out these.

1. Canaan Avalon Nano 3: The Canaan Avalon Nano 3 is a small and affordable home miner that also works as a heater. It can hash up to 4 TH/s and uses only about 120-130 watts of power, making it quiet. Priced around $100, it’s a great entry-level option. You can place it anywhere in your house since it has Wi-Fi. It can also warm up a room in a short amount of time. It's the first home miner from a big company like Canaan, and they will likely continue making similar devices.
2. Bitaxe: The Bitaxe Project offers a distinct approach, not solely focused on heating but rather as a low-power and cost-effective mining solution. Rooted in an open-source ethos, it repurposes ASIC chips, such as the BM1366 ASIC from the S19XP, into single-board configurations. Despite its modest hash rate of around 0.5 TH/s due to the use of a single chip, it excels in terms of energy efficiency, boasting an impressive 24 J/TH and consuming only 12 W. Moreover, ongoing developments promise more powerful Bitaxe solutions with multiple chips on the same board, enhancing its mining capabilities. This miner is more used as a "lottery miner" by mining in solo mode on pools like the Public Pool or the CK Pool.

Both of these alternatives are available for purchase, with worldwide shipping, through the D-Central shop. D-Central, a reputable e-commerce platform based in Canada, has established a strong track record for customer service and reliability in the mining community.

👉 Click here to view the available home miners & space heaters on D-Central.

Bitmain Antminer S9i Pros & Cons

While testing the Antminer S9i for weeks, I noticed that many people don't mention the several downsides of using this miner at home. If you have free electricity and plan to use the S9i in a mining farm or away from home, it's a great choice. But if you want to run it at home, consider a few things. You'll need to follow guides to install aftermarket firmware to underclock it, change at least the PSU fan, and make other tweaks to reduce noise and adjust power use.

Also, while the S9i works as a great heater in winter, it generates a lot of heat in the summer, which can disrupt the life of your family or the other people living in your house, especially in hot areas. If you want to fix this, you'll need to buy a fan shroud and an aluminum foil ventilation hose to vent the hot air outside.

Bottom Line

I still have a lot of respect for the Antminer S9i, but it's important to point out that this miner might not be for everyone. There are several downsides that might make people choose more efficient and quieter home miners/heaters.

With companies like Canaan introducing home miners like the Avalon Nano 3, the Antminer S9 is starting to make less sense for beginners for the first time in almost 10 years. However, it's still an interesting option because of its very low price (you can find it for as low as 50 bucks used on eBay), decent hashrate, and ability to quickly heat large rooms. It also has great educational value, helping you understand how a miner works and providing fun as you customize and tweak it with many available aftermarket accessories/kits.

Bitmain Antminer S9i Evaluation

The Bitmain Antminer S9i got a blockdyor Score of 68 out of 100.

Profitability: This miner has a profitability rating of 98.2 J/TH. While it's far away from modern miners, this can be upgrade with aftermarket firmwares.

User-friendliness: If you don't have some hardware/software experience, it will take a long time to customize and setup this miner, because it needs some work both on the hardware (more silent fans) and software (aftermarket firmware).

Compatibility: You can both pool mining or solo mining every SHA256 coin with this miner.

Reputation: Antminer, the manufacturer, has a somewhat average reputation. This is because, according to many, they don't deliver the highest quality in their miners. However, I noticed that the build quality of this miner was ok.

Cost: The price point is the lowest of most of the miner over 10TH/S you can find now on the market. But since the power consumption is very high, if you include also this in the cost, expect an high possession cost.

Frequently Asked Questions (FAQ)