How to DIY an Ethereum Mining Rig for Beginners

Ethereum mining rigs can cost a fortune, particularly in power costs. Fortunately, it’s possible to create a DIY mining rig that uses very little power. This article explains how to build your own cheap Ethereum mining rig.

DIY Ethereum Mining Rig Efficiencies

The most efficient GPU miner of Ethereum at present is the Nvidia GTX 2070 8GB. It mines at around 42 megahashes per second (MhS) using 170 watts of power. That’s around 4.048 megahashes per watt (MhS/w). But the ASIC miners, custom chips designed to run the Ethash algorithm, beat out even the most efficient GPU miners. Unfortunately, they both cost hundreds of dollars and are priced out of reach of most small-time miners. On top of that, they’re useless for anything other than mining.

For those who don’t have the money to build a high-end miner, you are best off using a low-cost, high-efficiency mining rig.

There are two approaches to reducing power costs when mining Ethereum (or any cryptocurrency):

  1. You can reduce the total wattage consumption of the system.
  2. You can maximize the amount of cryptocurrency mined relative to its power consumption.

Both design styles end up looking very similar to one another. That’s because cryptocurrency mining focuses on two parts: the graphics card and the power supply. The rest of the computer can be little more than scrap pulls.

Let us begin with the most important component: the Graphics Processing Unit (GPU).

Parts for Building Your Ultra-Efficient Miner

Energy-Efficient GPUs

The most energy-efficient mining devices for Ethereum are dedicated ASIC miners. But those cost a fortune. Most people are better off creating a low-cost, high-efficiency miner and then using the computer for other purposes after they are finished with it.

The best GPUs should offer the highest hashrate inside of 75 watts. The reason for this is that 75 watts is the maximum output of the PCIe slot which the GPU is connected to.

More or less, if you want energy efficiency (without paying a fortune for a 1060, 1070, or 1080), your only option is an AMD graphics card. The most energy efficient of these is the AMD Radeon RX 460 or RX 470 (or the pricier RX 560 and RX 570). The RX 470 pulls around 145 watts, with the recommended power supply for it produces around 350 total watts.

The RX 550 on the other hand, uses a total of 50 watts. That makes it easier to deploy on single-card mining rigs.

AMD Radeon RX 460

The hashrate of the RX 550 is reported to be around 11 mega-hashes per second (MhS). With a “peak” wattage consumption of 50 watts, that translates to 0.22 MhS/W. The 570 produces a hash rate of around 25 MhS with a power consumption of around 120 watts for 0.208 MhS/W. Of the two, the 550 offers better efficiency per watt and is easier to deploy on low-cost, low-end systems.

Note: The more GPU video RAM, the better the hash rate of the card. If you can get more RAM, do it.

RX 550, 460, 560 GPUs Are Easier to Power

GPUs like the RX 470 and 570 require additional power from either a 6-pin or an 8-pin connector, supplied by your power supply unit (PSU).

The RX 550, 560, and 460 draw so little power that they can operate entirely off the power supplied by the motherboard’s PCIe connector (which maxes out at around 75 watts). That means you don’t need an 8- or 6-pin connector, so it can almost certainly operate off the energy supplied by what’s known as a picoPSU: a tiny, fanless, highly-efficient PSU.

Energy-Efficient Power Supply

The power supply determines how efficiently a computer pulls current from the wall socket. Unfortunately, the standard PSU converts from wall current (Alternating Current, also known as AC) to Direct Current (DC) at around 70 percent efficiency. That means 30 percent of the power pulled from the wall gets turned into waste heat.

Fortunately, a variety of PSUs can convert at 80 percent and higher. When certified by the 80 Plus organization, a power supply unit receives an efficiency rating which varies depending on the load of the unit.

The ratings vary between 80+, 80+ Bronze, 80+ Silver, 80+ Gold, 80+ Platinum, and 80+ Titanium. At the highest end of the spectrum, PSUs produce above 90% efficiency at all loads, but they tend to cost a fortune.

I prefer using what’s called a picoPSU. A picoPSU generally supplies power somewhere under 200 watts. It also tends to offer higher efficiencies than standard power supplies, at 80-90% efficiency. If you’re using an RX 550, 460, 560, you can get away with a picoPSU. The model I recommend is the 160-XT. The XT includes a 4-pin CPU connector.

However, many Intel J-series motherboards have soldered-on processors that don’t require a 4-pin power port. That reduced build costs.

Mini-Box picoPSU-160-XT High Power 24 Pin Mini-ITX Power Supply

Mini-Box picoPSU-160-XT High Power 24 Pin Mini-ITX Power Supply

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On the downside, you can’t just slap a picoPSU into a case without making modifications. For example, I had to run the DC power jack through my case’s three-pronged female port. On top of that, picoPSUs usually only support a single SATA-powered device. If your case places its storage drives in odd places, you might also need an extension cable.

PSU Case Modification with 3D printed bracket.

Best Motherboard and CPU for Ethereum Mining

There is only one requirement for the motherboard: it needs to support a full-size GPU. The processor doesn’t matter. You need a PCIe x16 slot.

I recommend using either Intel’s J-series “Atom” motherboards with embedded processors. Alternatively, AMD’s socketed AM1 platform offers a modular alternative. Both are fine motherboards although if you ever want to play games, they are for low-end gaming only.

A few of Intel’s J-series boards now include PCIe x16 support. However, there’s confusion regarding how much power the PCIe slot produces. According to its specifications, a PCIe x16 slot can deliver around 75 watts. That should be enough to handle the 75-watt draw of many midrange GPUs, like the Nvidia 1050 Ti and RX 550, 460, and 560.

Not all of these cards require it, but some manufacturers include an optional 6-pin GPU power connector for added safety.

This is a photo of a PCIe x16 port on an AMD Kabini ITX motherboard.

Note: You might notice that some motherboards are PCIe x16 at x4 speeds. Cryptocurrency mining only requires a PCIe x16 port for its physical size and ability to supply 75-watts of power. The bandwidth of the port does not matter to miners.

The Rest of the Computer

The rest of the computer doesn’t matter much. In general, you want a case that can adequately cool either an RX 460, RX 560, or RX 550—but GPUs include their own cooling mechanism. The case only needs to not interfere with the GPU’s fans and provide enough space to house the graphics card.

Some people even choose to do open air builds. An extreme few daisy chain together multiple 570 GPUs on Ikea storage shelves!

Sample Build: Super Low-Energy Ethereum Miner

Here’s what my ideal low-power, budget build looks like:

  1. Motherboard + CPU: ASRock J4005B-ITX (Amazon)
  2. GPU: Sapphire Radeon RX 550 4GB ($95 via Newegg)
  3. Case: Silverstone SG05-LITE Sugo ($43.99 via B&H)
  4. RAM: Crucial DDR4-2400 1 x 4GB SO-DIMM (Amazon)
  5. SSD: Crucial BX500 120GB (Amazon)
  6. picoPSU + power brick: 120-watt unit ($65 via Mini Box)

Total wattage consumption: 75-95 watts
Estimated hash rate: 14 MhS
Hashes per watt: 14 MhS/100 W = 0.14 MhS/W

A  more expensive miner would use a beefier PSU and GPU, but otherwise it should look identical. For beginners, I don’t advise anything stronger than an RX 560. The supporting infrastructure of a bigger GPU, such as a high wattage power supply unit, can invisibly increase costs. If you’re new to mining, you should do everything possible to minimize build costs and power consumption.

This is a picture of the Silverstone Sugo Mini-ITX computer case.

There is more you can do to this system. The Solid State Drive (SSD) makes boot and configuration time faster, and you could double the RAM by purchasing two 4GB SO-DIMMs instead of one. This would slightly increase the hash rate and make it more usable as a lightweight gaming computer.

Configuring Your Miner: Undervolting Your GPU

Like with CPUs, you can reduce the voltage supplied to the GPU and decrease the power consumed and waste heat produced. Whether there’s a trade-off depends on the silicon lottery. Most discrete graphics cards can undervolt slightly (what is undervolting?) without losing anything. However, a small number become unstable, even with slight undervolting. You won’t know until you try.

If you have an AMD card, it works like this: install Radeon Settings. Run it, and then go to the Gaming Tab:

This is a screen capture of the Radeon Settings menu.

Choose Global Settings:

This is a screen capture of the AMD Radeon Settings menu and someone is clicking on Global Settings.

Choose the Wattman tab and scroll down until you reach the entry for Voltage Control (mV). From within this menu, you can reduce the voltage. However, keep in mind that your GPU draws a different voltage at each frequency. Personally, I use a 100 mV undervolt at each frequency.

So, for STATE 1 through 7, I reduce the voltage by 100. The lowest it can go for the RX 480 is 800, so you’ll notice that the first two entries are at 800:

This is a screen capture of the Wattman settings with the voltage being tweaked.

If this makes your system unstable, Radeon Settings will automatically reset to the default voltage. There is virtually no risk of permanent instability. In the worst case scenario, you can simply remove your graphics card.

Should You Build an Energy-Efficient Ethereum Miner?

I’d say only as an experiment. The underlying technology behind Ethereum is a big leap over Bitcoin’s. But cryptocurrency is so ridiculously speculative, it’s only worth taking a moderate risk on, even if you understand cryptocurrency. I wouldn’t invest thousands into mining unless you really have thousands to spare, and make sure you’re aware of the risks before spending any money.

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