How to build your own mining rig

Which components should you choose for a graphics card mining rig, in what order should you assemble them and, above all, how do you power everything safely? In the very first video on our channel (in French), we build a rig of 8 RTX 3060 Ti LHR cards from A to Z, presenting every part and every connection.

Video from September 2021: the figures below date from that time. See "What about today?" at the end of the article.

1. The rig's components

• Frame: open, aluminium, with 120 mm fans, 5 on each side. You need fans at least on the side where the hot air leaves the cards; we fit them on both sides, to bring in fresh air and extract hot air.
• Power supplies: two 1000 W Corsair RM units, 80 Plus Gold, with 100% Japanese capacitors. Being modular, they let you connect only the cables you need. The PCIe cables supplied are never enough: we added extra ones.
• Motherboard: Intel B250 chipset, socket 1151, with 12 PCIe slots (one x16 and the rest x1) and DVI and VGA outputs. Its extra power connectors are not needed: the risers have their own power.
• Processor: an Intel Celeron G3930, which is enough because graphics card mining needs no CPU power.
• RAM: DDR4 at 2400 MHz; 4 GB is enough.
• Storage: a 120 GB SSD running HiveOS, an operating system dedicated to mining that can be managed remotely.
• Risers: 009S Plus models, with twice as many capacitors as standard 009S risers (8 instead of 4).
• Fan hub: 8 three-pin ports, which also accept four-pin fans.
• Graphics cards: MSI Ventus cards with three fans, very good value for their price, Gigabyte Eagle cards and more basic Inno3D cards. Their GDDR6 memory runs much cooler than that of the RTX 3080 and 3090. Average price paid: €630 including VAT.

These cards are very well suited to Ravencoin, Ergo, Firo or Flux; the rig will most likely mine Ravencoin. At €630 per card, we calculated a payback time of less than 9 months, with one caveat: the Ravencoin halving due in January would cut miners' earnings in half.

2. Preparing and testing the motherboard

1. Processor: find the alignment notch so it goes in the right way round, then lock the socket lever.
2. RAM: start with the DIMM1 slot, as some motherboards require a specific order.
3. CPU cooler: the stock Intel cooler already has thermal paste applied. Push in the 4 fasteners until they click and connect it to CPU_FAN.
4. Power button: it goes on the buttons and LED header at the bottom of the motherboard.

Our advice: the first time, start the motherboard without any graphics card, with the monitor connected to the DVI or VGA output (the processor's integrated graphics). The BIOS lets you choose whether the display goes through the motherboard or a graphics card.

3. Wiring the main power supply

With the motherboard screwed onto the frame's standoffs and the power supply in place, first connect the motherboard's 24-pin connector, the CPU's 4/8-pin connector, then a SATA cable for the SSD and the fan hub (a second one if needed, to avoid crossing cables). We put 4 graphics cards on each power supply; the motherboard and processor draw no more than 100 W.

4. Powering the risers safely

This is the crux of the build. A PCIe cable is designed for 300 W in total, and each of its two 6+2-pin outputs for 150 W. A riser delivers up to 75 W to the graphics card through its PCIe x16 slot. So:

• one 150 W output can power 2 risers;
• 3 risers on one PCIe cable, i.e. 225 W: this is what we recommend, to keep a safety margin;
• 4 risers, i.e. 300 W: this is the cable's limit.

Golden rule: never power a riser with a SATA cable. The SATA standard is limited to 54 W, well below the 75 W a riser can draw: the cable can heat up and then melt. The small SATA cables supplied with risers go straight in the bin. Molex can handle more power, but is still not recommended.

5. Connecting the second power supply

To make a second power supply start together with the first, you use a power supply coupler (Add2PSU type), powered by a Molex cable from the main power supply. The second power supply's 24-pin connector plugs into it, and the coupler passes on the start signal.

6. Installing the risers and graphics cards

1. Power the riser with a PCIe cable.
2. Connect its USB cable to any PCIe x1 slot on the motherboard.
3. Insert the graphics card into the riser's PCIe x16 slot until it clicks.
4. Screw the card to the frame's crossbar.
5. Power the card from an available PCIe output.

Finally, group cables of the same type (PCIe, SATA) with ties or Velcro.

What about today?

Since Ethereum moved to proof of stake on 15 September 2022, income from graphics card mining has collapsed: the prices and payback time given here no longer apply. The power rules (power budget per PCIe cable, no SATA for risers) still hold, but miners today mostly turn to ASIC miners.

To set up this kind of rig, follow our HiveOS tutorial. To mine today, browse our ASIC miners and power supplies, or contact us for advice before you buy.