Choosing mining hardware: component parts, models, and producers
We are happy to present a series of authors' articles by our friend, who will tell you about his experience as a miner. He will explain to you step by step how to build a farm, avoid the mistakes of a beginner, and even sell it without significant losses if you decide to quit.
Hi there! My name is... Never mind! All that matters is that I’m a miner. I've been mining for three years, assembling rigs to order, consulting on purchases and operations, and running a small 23-rig farm. Allow me to share my experience with you in a series of five articles on:
- Choosing mining hardware and facilities: component parts, models, and producers;
- Configuring mining software: updating BIOS, automatic rig activation, video card BIOS firmware, video card overclocking, remote monitoring, and control;
- How to organize a mining farm: choice of location, ventilation, and smart home system.
- Maintaining a farm: monitoring, backup hard drive, cleaning, health checks, minor repairs, and warranty returns;
- Quitting mining: selling the hardware, service life of video card memory, and financial loss.
Today we’ll focus on choosing the hardware. I took up mining quite late: it was 2017, the Bitcoin rate was skyrocketing, and video cards and motherboards were out of stock in every single store. Back then, I had to buy whatever I could find, which allowed me to try out different combinations of hardware models and producers.
Video cards vs ASICs
The first item on the agenda was the mining method. Cryptocurrency is generally produced by means of lengthy and complex calculations. In the case of popular cryptocurrencies, such as Bitcoin or Ethereum, we would generally use video cards or Application Specific Specialized Circuits (ASIC). The latter are more efficient, they consume less power, and can produce Bitcoin, but quickly become obsolete and have no value on the aftermarket. I went with video cards: at least they can be reused for gaming. Next up were the rigs, specifically assembling and configuring them properly to ensure maximum efficiency.
What you need for a video card-based rig
A rig is one of the elements of a mining farm. Simply put, it is a computer, if what you’re using is video cards. In fact, it’s a regular computer many gamers own, with one distinctive feature: it has many video cards! A rig is composed of:
- A motherboard with an up-to-date chipset;
- One or a couple power supply units;
- A processor (affordable ones work, too);
- RAM of any producer and model; recommended capacity: 8G;
- A data storage unit;
- An enclosure;
Mining is not demanding of RAM speed or processor and hard drive performance. However, they do not come for free, so installing multiple video cards into one rig will save you money. The recommended number of video cards is 7 to 8, as the market rarely offers motherboards supporting the simultaneous operation of more video cards.
The first thing to keep in mind when choosing a mining motherboard is that it should have at least six PCI-E slots of any capacity, either with an x16 or an x1 connector. The video card can also be connected via a special adapter to an M.2 connector generally used for SSDs or Wi-Fi boards. Opt for a board with a modern chipset and an Intel 1150 or 1151 socket, as they are the only ones to support 7 to 8 graphic accelerators. I recommend Asus Z270-A Prime or Z270-P Prime. Those are reliable motherboards guaranteed to work for mining. Up to 8 cards can be connected, BIOS can be easily updated online, and the board itself has ON and RESET buttons. Those are the motherboards of my choice as they run smoothly. You may consider buying specialized mining boards, like ASRock H81 PRO BTC. Those are guaranteed to have no trouble with the simultaneous operation of video cards, but the demand for such boards is generally low on the aftermarket. Once you've assembled the rig, it’s time to take care of the risers. Here’s what my experience was like.
You can't insert 7 to 8 video cards directly into a motherboard since a video card has PCI-E 1x connectors instead of 16x, and if that weren’t an issue, you would still need to eliminate heat from the densely placed cards. That is why we use the so-called risers, a sort of extension allowing us to place video cards away from the motherboard. Risers don’t vary in efficiency, but they do have different reliability characteristics and power connectors. When it comes to risers, reliability is your top priority, so I wouldn’t try to cut corners here. Some miners recommend risers of specific colors or shapes, but that's not how I would go about choosing one. Their quality varies from batch to batch, regardless of their appearance. Always get a spare riser per rig just in case, opting for more expensive ones. Risers come with Molex, SATA and 6-pin connectors. In my experience, the ones with Molex work perfectly provided the power supply unit has enough of such cables. We’ll focus more on that in the power supply section.
Deciding on the power supply
Mining causes video cards to consume colossal amounts of electricity. One video card consumes about 180–230 Watt, which is why 7 cards would require a 1,600 Watt power supply to allow for a backup of 10–15 %. Consider power supply units certified under 80 PLUS Bronze or higher to maximize the energy efficiency of the farm and reduce heat. There is a number of ways to achieve this kind of power:
- Two regular power supply units of at least 750 Wt and 650 Wt. That is barely enough for a rig with 7 RX 470 video cards. It’s essential to stick to the right starting process: the processor's power supply unit is the last to start, which is why it is recommended to use a power supply synchronizer. Alternatively, you could start the power supply using a bridge; it works perfectly for me. Please note that although the option with two PSUs is the most expensive, it is not the most reliable one. The units work at their full capacity, which is frequently the cause of burnt connectors.
- A re-purposed server power supply unit. It’s cheap, but you need to resolder the power supply braid, which is not easily scalable. That is why I've never tried this option.
- A China-made mining power supply unit. I’ve always been skeptical about this category, finding it hard to believe that one unit can provide 1,600–1,800 Watt, much less at this price. My experience suggests, however, that China-made PSUs have a longer service life than branded ones. Additionally, Chinese producers seem to have taken care of everything, supplying each unit with a lot of reliable Molex connectors, long flexible cables, and three coolers. Unfortunately, I cannot give you any specific names as they may change from batch to batch. Here's a trusted PSU you can get on Aliexpress.
As I've mentioned earlier, it’s a good idea to match the power supply unit and riser connectors. First, that saves you the trouble of searching for and buying adapters, and second, extra connections reduce reliability: a riser is supplied with up to 75 Wt of power, which may cause overheating of the adapters’ thin wires.
Choosing an enclosure
Regular enclosures won’t do for miners who use video cards due to the size of the latter and the immense amount of heat they produce. My first pilot rig was enclosed in a... box! This chaotic bunch of cables through which you could see the motherboard’s LEDs only produced 116 MH/s, as overclocking didn't work, and the video cards were overheated. It’s better to use specialized enclosures; in most cases, these are open structures made of wooden bars or aluminum profiles. The wooden ones are cheaper and guarantee short circuit resistance (you can safely install the motherboard without insulation), but they are heavy and take up more space. The metal housing is more elegant, needs less room, and won't catch fire.
It's time to choose a hard drive
This is the easiest part. If you use Linux, an 8–16 GB drive will do; if you are a Windows 10 user, you’ll need a drive of at least 40–60 GB. It’s definitely better to get an SSD, as it ensures faster system loading, updating and running, but it’s totally optional. I wouldn’t recommend using a USB flash drive as a hard drive, as due to multiple read and write cycles they don't last very long. Also, a USB flash drive can only be used with Linux.
The most important part: video cards
Here’s where it gets complicated. Even if I wanted to, I wouldn’t be able to cover a wide selection of video cards in this article; but I’ll outline the general rules for choosing a mining video card based on my personal experience. Then we’ll compare the performance of specific models in set implementations.
- There’s no point getting “mining” video cards: their inner workings are the same, but they come with shorter warranty and are harder to sell on the aftermarket.
- Using gaming versions makes sense, as they often have better cooling. Gigabyte’s RX 740, for instance, has a metal plate on the rear cover.
- Video card quality varies greatly from producer to producer. That’s important for video games too, let alone for mining. In my experience, the best video cards are produced by Gigabyte. They have a good efficiency/energy consumption ratio, most of them use good Samsung memory chips and have well-designed cooling (the fans do break from time to time, but I’ll cover that in a different article). Sapphires are okay, too, provided they have Samsung memory.
- Opt for video cards with the most powerful cooling system. If you’re choosing between a two- and a three-fan card, go with the three-fan one.
- Overclocking capacity and therefore hash rate are defined by the memory chip producer. Samsung memory provides the most stable operation. On Gigabyte Radeon RX 470 4096M, for instance, it easily overclocks to 2,100 MHz, which gives you an impressive 29.5 MH/s. Elpida, on the other hand, is notorious for its recurring errors at over 1,950 MHz.
- If you mine Ethereum, the memory capacity has to be more than the DAG file: as I’m writing this article you need 4 GB, by the end of 2020 you’ll need 8 GB.
Hash rates of some video cards are specified in the table below along with my rating:
|Name||Hash rate, MH/s||Core frequency, MHz||Memory||Rating|
|Gigabyte Radeon RX 570 4096M||29.43||1,100||2,050||SK Hynix H5GC4H24AJR|
|Gigabyte Radeon RX 470 4096M||29.5||1,100||2,100||Samsung K4G41325FE|
|Sapphire Radeon RX 470 4096M||24.5||1,000||1,950||Elpida EDW4032BABG|
|Sapphire Radeon RX 470 8192M||29.16||1,100||2,100||Samsung K4G80325FB|
|Palit GeForce GTX 1080 8119 MiB||35.06||1,620||1,155||?|
Some cards are mentioned twice to give you an idea of the hash rate/overclocking ratio. Memory tends to wear out, so you have to reduce the frequency to eliminate errors. We hope that this guide will help beginners understand from where to start. Keep an eye on our news so you don't miss the next article where our guest will dive deep into mining software configuration. Stay tuned!