Build a Ethereum Mining Rig

For the first time, I am building a ethereum mining rig myself and now I want to share my experience with you. For the case, I have used a very simple wood construction for less than 10€. Here is the sketch:

The following hardware has been used:

ASRock H61 BTC Pro

Intel Celeron Dualcore CPU

Cheapo 2x4GB RAM

6x cheap powered rises for about 5€ from ebay (I later cut some loose cable endings just to make sure there are no short circuits)

2x Corsair CX750M 750W PSUs

As for the graphics cards:

3x Sapphire Radeon HD 7970 @ 1050/1375

2x Club 3D Radeon HD 7950 @ 880/1250

1x MSI Lightning Radeon HD 7970 @ 1200/1500

I have benchmarked the single cards as well as the temperature in a closed room after the rig has been running all night.

Adapter 0 – Sapphire 7970 @ 1050 / 1375: 24,0 MH/s Sensor 0: Temperature – 83.00 C

Adapter 1 – Club 3D 7950 @ 925 / 1250: 21,9 MH/s Sensor 0: Temperature – 88.00 C

Adapter 2 – Club 3D 7950 @ 925 / 1250: 22,2 MH/s Sensor 0: Temperature – 82.00 C

Adapter 3 – Sapphire 7970 @ 1050 / 1375: 25,4 MH/s Sensor 0: Temperature – 78.00 C

Adapter 4 – Sapphire 7970 @ 1050 / 1375: 24,4 MH/s Sensor 0: Temperature – 82.00 C

Adapter 5 – MSI Lightning 7970 @ 1200 / 1500: 28,9 MH/s Sensor 0: Temperature – 76.00 C

The system a total power consumption of about 1440 Watts at the wall (230VAC), delivering a stable hashrate of ~147MH/s. As I bought almost all parts used, I paid about 900€ for the complete rig.

What would I do different now? First off, I would make the feet of the rig stand out at the bottom, so it is stackable. Probably it is also a better idea to have the PSUs on the outside of the rig. For mounting the cards, I have better used M3 screws, and the cards should no hang as high as they do now, because I had trouble with the first PCI-e riser on the very left being to short. Also, the conventional HDD is producing a lot of heat, SSDs are so cheap that I would definately go with one of these.

With the next rig, I will peek into how the Radeon HD 7990 performs, as those are 2x7970s on a single cards, with promising 50MH/s for about 375 Watts. The 7950’s are better on the paper, but actually they run very hot a low clocks. Changing the thermal paste to a metal liquid paste and clocking the down prevents them to go up in fire, and that’s all I can say about those. As soon as I can get some 7970s to replace them, I will do so.

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Update:

My PSUs don’t have six PCI-E connectors. I have used adapter to squeeze out 2 additional ones on each, but I made sure that every cards a least gets a main PCI-E power connector (ie. two cards 1x PCI-E from PSU and 1x through adaptor, one card 2x PCI-E from PSU. If you have different cards, try to make the stronger ones having the two original PCI-E lines). Do not mix PCI-E lines between adaptors, keep them separated, ie. PSU1 will power cards 1-3, PSU2 will power cards 4-6. I advise using those risers with USB cables, I have both the types of risers and bought twice.

If you do not follow this wiring scheme you risk shorts or unbalanced power distribution, leading to overload and/or bad power efficiency.

Wiring plan :