BTC-S37 rig build (temps, HiveOS, etc.)
The BTC-S37 is a motherboard with an unusual layout: the graphics cards plug straight into it, with no risers. That makes it attractive to anyone who wants to avoid risers, but space between the cards is tight. In this video (in French), we build a complete BTC-S37 rig on an open-air frame with four graphics cards, start it up under HiveOS and look at the performance and, above all, the temperatures.
Video from 2022: the figures below date from that time. See "What about today?" at the end of the article.
1. The hardware
- The BTC-S37 motherboard: it has 8 PCI-Express slots, one per graphics card. It is often installed in a closed case; here we install it on an open-air frame. The spacing between two PCI-Express slots is about 7 cm.
- Memory: one stick of DDR3 1600 RAM in SO-DIMM format, to be fitted before placing the motherboard on the frame.
- Storage: an SSD.
- The frame: an open-air frame designed for the BTC-S37, with four fans mounted on one side. You can add four more on the other side to create an intake and exhaust airflow.
- The power supply: a 2,000 W Chinese PSU, very good quality in our view, with well-made cables, but a little noisy.
- The graphics cards: GTX 1660 Super and RX 6700 XT cards, making it a mixed NVIDIA and AMD rig.
2. Powering the motherboard and the fans
Depending on the version of the BTC-S37, the power supply does not start on its own. In that case you use a small plastic adapter that bridges the power supply on itself; failing that, you connect the two relevant pins with a paperclip.
The motherboard has its own 6-pin PCI-Express power connectors, one for each of the 8 slots. You must connect at least the first one, closest to the processor, then every connector that matches a slot holding a graphics card. The graphics cards then get their own power cables.
For the frame fans, which use a 3-pin (sometimes 4-pin) connector, there are two options:
- the power supply's 4-pin Molex cables, if the fans have a Molex connector;
- a fan hub: powered over SATA like the SSD, it has a button to switch it off or to a high setting, and takes up to 8 fans.
3. Test the motherboard, then install the cards
Before fitting the graphics cards, we connect a screen to the motherboard (HDMI output, there is also a VGA port) to check that it boots and displays correctly.
We then install the four cards. They fit, but with very little room between them. Slim cards such as the GTX 1660 Super or the RX 6700 XT are fine; with thicker cards, from an RTX 3060 or 3060 Ti upwards, they are likely to end up pressed right against each other. This is the main thing to check before choosing a BTC-S37 on an open-air frame.
4. Setting up HiveOS
The rig is managed remotely from HiveOS. Since it is a hybrid rig, the overclocking screen lets you set the NVIDIA cards on one side and the AMD cards on the other, card by card or all at once.
- GTX 1660 Super: the memory setting is not the same depending on whether the card has Micron or Hynix memory, so you need to know your cards a little.
- RX 6700 XT: we knew this card less well. We used HiveOS's popular presets: you choose the coin (overclocking depends on the algorithm), Ethereum here, then the card model, and pick a widely used setting, here with a core clock of 1300.
The flight sheet mines Ethereum with software that works with both NVIDIA and AMD cards. The result: 31.5 MH/s on the GTX 1660 Super, as expected, and 46.9 MH/s on the RX 6700 XT.
5. Temperatures, the weak point of open air
With the fans set to 70%, temperatures climb quickly. One GTX 1660 Super goes past 60 °C and one RX 6700 XT already reaches 65 °C, which is fairly high. The hottest cards then settle at around 65 to 67 °C. By contrast, the RX 6700 XT at the edge of the rig stays at a relaxed 40 °C: it is the cards squeezed in the middle that suffer.
The open-air frame does have a real advantage: it is relatively quiet. In closed cases, the fans spin at 3,000 to 4,000 rpm and are very noisy. Paradoxically, a closed case therefore makes more noise than an open-air frame.
To improve cooling in open air, we suggest adding fans at the back, pointed directly at the cards.
What about today?
Since Ethereum moved to proof of stake in September 2022, Ethereum can no longer be mined with graphics cards: the hashrates above are out of date. The building advice (spacing between cards, powering the slots, airflow), however, still applies to any multi-GPU rig.
To go further, read our comparison of the BTC-S37 in a closed case vs open air, browse our multi-GPU kits and frames and find all our guides on the tutorials page. A question about your build? Contact us.