BTC-S37 rig: closed case vs open-air
Should a BTC-S37 rig go in a closed case or on an open-air frame? After our open-air build, this time we assemble, for the first time, a closed case designed for the BTC-S37 motherboard. In this video (in French), we then compare the two options with the same six graphics cards, measuring temperatures in HiveOS and noise with a sound level meter.
Video from 2022: the figures below date from that time. See "What about today?" at the end of the article.
1. Assembling the closed case
The case comes with large industrial fans that blow very hard, at around 4,000 rpm. Since it is designed for the BTC-S37, the standoffs are already in place: all that is left is to screw in the motherboard with the small screws supplied.
- Power button: a power switch lets you turn the motherboard on from outside the case. It connects to the usual two pins.
- Fans: they are 4-pin, and the motherboard happens to have four 4-pin headers. It feels as if everything was made to fit.
- Power supply: a 1,600 W Chinese PSU, good quality, supplied with plenty of cables. The case has a dedicated bay: you slide the PSU in and secure it with three screws. Very practical.
- Cabling: we advise routing the cables you don't need, such as the CPU cable, to the other side. The motherboard has no 24-pin connector, so you bridge the PSU's 24-pin connector on itself to make it start. There is room to spare; the case is really well designed.
- Storage: a standard SSD connected over SATA. An mSATA SSD would be a little more practical.
Next, the motherboard's PCI-Express slots must be powered with 6-pin cables: here the first six, one per graphics card installed.
2. Installing the six graphics cards
We install six Asus Dual cards from the RTX 30 series, in LHR versions. They plug straight into the PCI-Express slots, then are screwed to their bracket for extra stability. This is the trickiest part of the build: there is very little room for your fingers. Our tip: use a magnetic screwdriver to hold the small screws.
3. Closed case: very cool cards, but a lot of noise
After about ten minutes of mining with T-Rex, the cards run at around 43 to 44 MH/s each, drawing a little over 110 W. With the fans set to 70%, temperatures are really low: 36 °C for the coolest, around 40 °C for the others, and the hottest stays below 50 °C. We should point out, however, that the place where the rig runs is not particularly warm.
The downside is noise. The sound level meter shows around 80 decibels, then about 70 decibels once the lid is on. Our finding: the closed case cools the cards very well, but it is very noisy.
4. Open air: less noise, but much hotter cards
The same six cards are then installed on the open-air BTC-S37 frame from our previous video. This time the power supply is a 2,000 W unit, noisier than the 1,600 W one. Since the frame fans are relatively quiet, it is mainly the power supply that determines how loud the rig is.
- Temperatures: clearly worse. The cards sit at 57 °C and 62 °C, then climb to 67 °C and 71 °C, and one reaches 75 °C (probably the one in the middle). Some run 15 °C, or even more than 20 °C, hotter than in the closed case.
- Noise: about 65 decibels on the meter. With a quieter power supply, we reckon it would barely reach 60 decibels. On this point, open air clearly wins.
5. The fix: an extra fan at the back
To cool the cards in open air, we place a standalone fan behind the rig. It is a basic model that cost about €50, with three speeds. At speed 3, everything turns green again in HiveOS: the cards are between 38 and 42 °C, just like in the closed case.
As for noise, the meter goes back up to around 70 decibels at speed 3. In our view, speed 2 would probably be enough and would save about another 3 decibels, and at speed 1 it drops back to around 65 decibels.
Our conclusion: an open frame works too, as long as you take care of airflow. You need fans on the other side of the cards, either a standalone fan like this one or more powerful PC-case-style fans fixed to the frame that blow hard. For us, this is essential to get the heat out from between the cards. The closed case, for its part, cools very well out of the box, but at the cost of much more noise.
What about today?
Since Ethereum moved to proof of stake in September 2022, Ethereum can no longer be mined with graphics cards: the hashrates in the video are out of date. The trade-off between heat and noise, however, is the same for any multi-GPU rig, and it also applies to ASIC miners, which are often very loud.
To see the open-air build in detail, read our article Building a BTC-S37 rig. If your ASIC is too noisy, find out how to build a soundproof box, or browse our quiet home miners. Any questions? Contact us.