Experiment: Build a (Profitable) Ethereum Mining Rig From Spare Parts

Building A Crypto-Mining PC: The Components You Can & Can’t Skimp On

In my search for hardware, I found an Intel Core i3-3220 CPU, an Asus P8P67 Pro motherboard, 2x2GB of G.Skill Ripjaws F3 DDR3-2000 memory, and a 128GB Sandisk SSD.

The Asus P8P67 Pro is a nice find for a mining system, because it has five PCI-e slots. There are three full-size slots: two x16 and one x4. It also includes two x1 slots that you can use if you have the proper riser cables.

The only power supply that I have in storage is an ancient PC Power & Cooling Silencer 750, which I wouldn’t trust to run 24/7 at peak power draw these days (it used to power my Core 2 Quad Q6600). To get me started, I used a 850W Corsair RM850, but I borrowed that power supply from another build, so I couldn’t use it for long. Eventually I bought the biggest power supply that I could find locally: a 1000W Corsair RM1000i.

Once I had all the base components, I tossed in a random GPU and loaded the operating system. In Eric’s experiment, he used a Lubuntu Linux distribution so that he didn’t have to buy an operating system. I’m operating on the assumption that you either own a spare copy of Windows or that you'd purchase a fresh copy for this build. I used Windows 10.

You Need More Than 2GB Of VRAM

Before starting this experiment, I already knew that 1GB of graphics memory wasn’t enough to load the Ethereum network’s DAG (Directed Acyclic Graph) file. The Ethereum DAG file started life at 1GB, but the platform increases the DAG file size at a rate of 750MB per year. Ethereum came out in 2015, which means the DAG file is now larger than 2GB. 

I decided to try a couple of 2GB graphics cards to see what would happen, but the mining software would not run on those cards. Instead of connecting to the mining pool, the miner software kicked back an error about the DAG file being too big for the available memory.

That revelation knocked several graphics cards off my list before I could even try them. I had to drop the Radeon HD 7870, R9 285, R7 370, and R9 380 2GB from the red team, and the GTX 750 Ti, GTX 760, and GTX 960 from the green team. I’ll explore the mining capability of those cards if I find another crypto currency that you can mine with them.

The Cards That Work

After removing the 2GB graphics cards from the test pile, I was left with 14 potential mining GPUs: five from Nvidia and 10 from AMD. Of course, I can’t use all of those GPUs at once, so I set out to find the cards that net the highest potential returns. I tested each card one by one to determine their power draw, waste heat, and hash rate.

[Note: Within our review of AMD's Vega 64, we include its mining performance, along with that of the RX 580, GeForce GTX 1080 Ti, and Titan Xp.]

The final GPU roundup includes some older and some newer graphics cards. The oldest GPU is a borderline ancient Radeon HD 7970 with 3GB of memory. As you might expect, the HD 7970 wasn’t able to keep up with the newer AMD cards. The old Radeon still laid waste to Nvidia’s 9-series cards, though. The HD 7970 managed to crank out roughly 12.4 MH/s. The GTX 980—an overclocked Asus Matrix Platinum edition—produced a paltry 3.2 MH/s. The GTX 970 and GTX 980 Ti samples were even worse, producing 3.01 MH/s and 3.02 MH/s, respectively. 9-series cards may work better with a different mining application. They don't work well with Claymore's Dual Ethereum Miner.

It’s no secret that AMD GPUs have traditionally been the dominant force in crypto mining. When it was still possible to mine Bitcoin with a GPU, Nvidia cards couldn’t mine fast enough to reach profitability, whereas AMD’s cards could easily push hash rates for good returns. Nvidia’s older GPUs still produce abysmal mining performance, but the tables have turned somewhat, and the company’s 10-series (Pascal) cards are much better at mining crypto coins.

Both the GTX 1080 and GTX 1070 produced higher than 20 MH/s, but surprisingly the GTX 1070 significantly outperformed the GTX 1080. The 1080 manages roughly 21 MH/s compared with the 1070's 24 MH/s, which puts it on par with AMD’s RX 480. It’s possible that with some tweaking, the GTX 1080 could perform better than the 1070. I ran all my tests at factory settings.

AMD’s R9 300 series cards are worthy options, too. My R9 380 cranks out 19 MH/s, and my R9 380X topped out around 20 MH/s. If you’re looking for raw performance and you're not worried as much about power draw, the R9 390 cards are tough to beat. The Sapphire R9 390 produced 28.5 MH/s, my air-cooled XFX R9 390X pushed 30 MH/s, and my water-cooled Power Color R9 390X Red Devil topped the charts with 31 MH/s.

I don’t have an R9 Nano or a water-cooled R9 Fury X, but I do have an R9 Fury on hand. It managed to produce 28 MH/s.

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