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

Ethereum’s mining difficulty is on the rise, and the crypto-currency's value seems to be on the decline thanks to so much mainstream attention. That's probably good news for gamers and general PC enthusiasts, but we also wondered if it's too late to get into crypto mining if you’re just trying to make a few extra bucks.

We recently explored the idea of building a mining rig at no cost, simply using older parts we had lying on the shelf. My colleague, Eric Vander Linden, cobbled together a competent mining rig with zero upfront costs. The “free miner” includes two R9 290X GPUs, which net roughly 57 MH/s. At the current difficulty rate, that rig should bring in a little more than half an Ether per month, which would be profitable as long as the price of Ethereum doesn’t dip below $100.

I also built a mining rig out of older components. Unlike Eric, I wasn’t worried about keeping the budget strictly at zero. I prioritized building the most powerful mining rig I could without buying specialty components. I was also interested in building an efficient miner to maximize profits. Still, I set my sights on something somewhat more exotic. Serious mining rigs often feature a half dozen graphics cards, or more, and I have the distinct advantage of a collection of older graphics cards packed away from past reviews and a handful of current generation GPUs I use for VR testing.

In total, I have 17 graphics cards that could work for mining—11 cards with AMD GPUs, and six cards with Nvidia GPUs. Unless you’re a hardware hoarder who never sells older parts, you probably won’t have such an advantage. A build like this wouldn't be free for most people, but we'd wager a few of you have some semblance of hardware sitting around anyway.

Regardless, I'm going to pick up where Eric left off. With a stack of graphics cards at hand, I am ready to go down the mineshaft. Will this be a fool's errand, or is there still gold to be found? Let's find out.

MORE: The Ethereum Effect: Graphics Card Price Watch

MORE: Best Graphics Cards

MORE: Best PC Builds

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  • badirontree
    THis is an EXTRA geto build :D
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  • badirontree
    *Ghetto
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  • bloodroses
    Next, add a Solar Panel/battery setup so you can get off the power grid. It will save you even more money.
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  • shrapnel_indie
    Interesting read. Unfortunately for me, I don't have the luxury of hanging to test products (for free, especially)... then again I don't have anything to test, beyond what I grab for my own use. I've got old hardware, but only one GPU with more than a Gig of RAM and I need that for my everyday driver.
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  • TJ Hooker
    Quote:
    Believe it or not, the Power Color RX 480, which is otherwise a very efficient mining card, dumps more heat into the room than any other GPU in this roundup. After a little more than 10 minutes of mining, the card reaches nearly 80°C.

    That's not how it works...
    There is not a direct relationship between GPU temperature and heat output (it also depends on the cooling solution). There is a direct relationship between power draw and heat output (they're equal). R9 390(X) are going to heat up your room significantly more than a 480.
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  • doktorv
    If you live in a hot region and use air conditioning, you actually consume more than double the listed electricity because the heat being produced in the computer has to be subsequently removed by the air conditioning, which is not 100% efficient. Texas might seem to be attractive for mining because the electricity is cheap, but if you do the full energy calculation you'll realize it's only worthwhile in the winter.
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  • Blake_24
    If you would plan to run this for a longer time, you should try to lower the clock speed on the GPU core to lower power consumption and increase the memory clock speed to increase hash rate. Since Ethereum is not very dependent on the core clock and basically only the memory clock it would make performance better while also increase the profit margin
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  • AnimeMania
    Could you write an article about how the cryptocurrencies get the money to pay to their miners. What they do with all the computations your graphic cards are making and if every time they increase the difficulty of mining a coin, does the additional calculations produce something of value or just create busy work. How safe is it allow somebody you don't know to have unlimited, unmonitored access to you computer.
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  • TJ Hooker
    Anonymous said:
    If you live in a hot region and use air conditioning, you actually consume more than double the listed electricity because the heat being produced in the computer has to be subsequently removed by the air conditioning, which is not 100% efficient.

    Yes, you need additional power to remove the heat via AC, but it's not double. An AC unit does not take 1 W to remove 1W of heat.
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  • JoeMomma
    Thanks. I needed that.
    Now if only they could rig a hamster wheel to a generator to help pay the electric bill.
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  • 1brianpburris
    How is $100 every 2 mos. profitable when you factor in electricity to run the beast.???
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  • takeshi7
    TJ Hooker, an AC unit takes MORE than 1W of electricity to remove 1W of heat. Air conditioning (and all heat exchangers for that matter) are not energy efficient. 2nd law of thermodynamics, and all that jazz. If he's pumping 1000W of heat into the room, he's probably using close to 1500W-2000W of air conditioning to offset it.
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  • takeshi7
    When you measured the Hashes/Watt efficiency, did you leave the cards at stock settings? I think you could have gotten much better efficiency results if you tuned the power levels of the cards.
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  • TJ Hooker
    Anonymous said:
    TJ Hooker, an AC unit takes MORE than 1W of electricity to remove 1W of heat. Air conditioning (and all heat exchangers for that matter) are not energy efficient. 2nd law of thermodynamics, and all that jazz. If he's pumping 1000W of heat into the room, he's probably using close to 1500W-2000W of air conditioning to offset it.

    No, they don't, I don't think you fully understand how a heat pump works.

    One measure of AC efficiency is EER. It's a measure of cooling capacity (in BTU per hour) by input power (W). A typical AC unit might have a EER of 10. If you convert the units, that's 2.9 W of heat removed per watt of power consumption by the unit. So your cooling costs would result in an extra ~33% on your power bill, not an extra 100% (double).
    https://energy.gov/energysaver/room-air-conditioners
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  • Ncogneto
    Great article, wish you would take it a step further and play with tuning the system to see how significant of a change you might be able to dial in. Also, In regards to heat, maybe it makes sense not to mine during the summer cooling months, but run it 7-9 months out of the year were the heat it produced would not be wasted completely? I understand it's not the most efficient way to heat a house, but, at least your not doubling down on your costs?
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  • RedJaron
    Anonymous said:
    How is $100 every 2 mos. profitable when you factor in electricity to run the beast.???
    Because if you only spend $40 or less a month on power, you're still netting $10 / month.
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  • extremepcs1
    Just a hypothetical, but say someone had (legal) remote access to 5,000+ normal desktop computers. If he/she were to install the software on them, could it be profitable? On-board Intel graphics type machines.
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  • TJ Hooker
    Anonymous said:
    Just a hypothetical, but say someone had (legal) remote access to 5,000+ normal desktop computers. If he/she were to install the software on them, could it be profitable? On-board Intel graphics type machines.

    Eth mining is memory-bound, and needs high bandwidth, low latency VRAM. Integrated graphics using system memory as VRAM would likely perform very poorly. Also, you would need to allocate > 2GB of system RAM as VRAM, so the machines would probably need to have >4 GB of system memory.

    If you're paying for electricity for these machines, I'm skeptical it'd be very profitable if at all.
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  • ubercake
    Does the mining process use much data bandwidth over an internet connection? If so, this would have to be added to the calculations in regions such as the outskirts of the Metro Detroit area where cable providers have no competition and have begun to implement data caps on cable internet.
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  • extremepcs1
    Quote:
    Eth mining is memory-bound, and needs high bandwidth, low latency VRAM. Integrated graphics using system memory as VRAM would likely perform very poorly. Also, you would need to allocate > 2GB of system RAM as VRAM, so the machines would probably need to have >4 GB of system memory.


    I was thinking along the lines of schools/universities where computer labs are running all day anyway. Like a background task kind of thing. Generate extra revenue for the school.

    If you're paying for electricity for these machines, I'm skeptical it'd be very profitable if at all.
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