Building an ethereum mining rig

jacobjacob Member Posts: 39
I have written a blogpost with detailed information about my experience building an ethereum mining rig with six Radeon cards. For those who are interested:


  • o0ragman0oo0ragman0o Member, Moderator Posts: 1,291 mod
    edited August 2015
    Nice. That MSI 7970 looks like a damn good card. Can't see any on the market ATM. :(
  • cpplovercpplover Member Posts: 38
    wow !!!
    Just Wonderful!!!
  • dabystrudabystru Member Posts: 13
    Nice. Anything on software setup, even if you followed standard guidelines?
  • soxminersoxminer Member Posts: 1
    Good job buddy. I'd remove those side panels. It's going to get pretty warm.
  • jacobjacob Member Posts: 39
    @dabystru Plain Ubuntu Mate 14.04, fglrx latest drivers through the "Additional drivers" windows. geth and ethminer. Actually, I was thinking of making a USB stick (16 or 32GB), so I can just dd it from one stick to another and have another miner set up with no hassle. Didn't have time for that really, though, since installation on a USB stick takes quite some time.

    @soxminer Yes, a friend of mine has a fabtotum, so maybe we can sew holes into the side panels for better air ventilation. The construction is super-simple and can easily build by everyone who can hold a an electric drill/screwdriver. You can get all the pieces cut at your hardware store in no time.

    @o0ragman0o Yeah, the MSI is damn good, definately would buy another one.
  • dabystrudabystru Member Posts: 13
    How did you connect 2 power supplies? Did you join their grounding contacts? Do they interconnect or power their parts separately?
  • jacobjacob Member Posts: 39
    First off, I am using "uncut" risers, ie the interconnection is made via the motherboard. I think it is important to use two PSUs of the same kind, though I have no technical proof that you really need that. I just went sure.

    I did not connect the Molex connectors on the H61 BTC Pro, rather I powered the risers three with each PSU. Then I made sure the first three cards are connected via the PCI-E 6+2 plug to the first PSU (which is powering the risers and mobo), and in the same way the other three cards. The second PSU is simply activated by connecting the green wire to ground on the mobo connector.
  • sandedsanded Member Posts: 20
    Regarding PSUs:
    I'm currently running two very different PSUs and I just shorted green to ground on the smaller one AND I connected both PSUs to share one common ground.

    There's a lot of non-information on that. A lot of text but almost nowhere a clear insightful explanation.
    The best I found was along the lines of "If there's some difference in potential you rather not want it to pass through the cards". But then there's other people mentioning ground loops... Don't know. Runs well so far.
  • o0ragman0oo0ragman0o Member, Moderator Posts: 1,291 mod
    From an electrical point of view, the tolerances are pretty tight, so any standard PSU should be pushing out the same effective voltages as long as the grounds are bound. The differentials would only be in millivolts and associated currents in microamps. I don't see a whole lot going wrong there.

    I would guess (serious?) issues could arise if the slave PSU is on without the master PSU powering the MOBO. In such a case 12V could be reverse injected into the motherboard by the GPU's on the slave and probably try to power the the GPU's on the master also through the PCIe rail. The whole systems would be put into an unknown and unpredictable electrical state which might cause damage.

    Even so, I would imagine that GPU's are designed to boot from PCIe 25W/75W power standard and then initiate the 6+2 rails when required. From that reckoning, I dare say that the 6+2 connectors would be in high impedance if the mobo was not powered and prevent any back injection.
  • jacobjacob Member Posts: 39
    Meanwhile, I have changed the risers from the ribbon styler risers to those with a USB cable. One of the graphics cards made "electrical noises" (like scratching when drawing power), which stopped now. Also, I have exchanged one 7950 for a 7990, which gave me some additional MH/s. Since those setup would draw too much power from my two 750 Watt PSUs, I have undervolted all cards with atitweak, now I have about 155-160MH/s drawing 1500-1550 Watts at the wall.

    Will post a detailed update soon.
  • index932index932 Member Posts: 10
    What are those "Powered rises" would you please point me to one of those in the market place like ebay or amazon.
  • MrYukonCMrYukonC Member Posts: 627 ✭✭✭
    index932 said:

    What are those "Powered rises" would you please point me to one of those in the market place like ebay or amazon.
  • guntisvitolinsguntisvitolins Member Posts: 24
    This here is what i use for my rigs, hope this is helpful to some of you :)
    If you are to lazy to build your own rigs, i have some fore sale!
  • guntisvitolinsguntisvitolins Member Posts: 24
    2nd part is out :)
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