From Unboxing to 56Gbps: The 5-Step Plan to Build a Home Server Supercomputer with ZimaBoard 2

Introduction

This blog post is published by Zima and is based on a video created by Zero , a Japanese tech content creator who has been exploring single-board servers and home lab experiments on his YouTube channel. We at Zima are deeply grateful to Zero for his enthusiasm, creativity, and willingness to push ZimaBoard 2 far beyond conventional use cases. The following is an editorial adaptation of his video transcript, restructured for readers interested in home server builds, networking hardware, and DIY supercomputing. All technical data, steps, and findings are preserved from the original content.

What does it take to build a supercomputer at home? For most people, the answer involves enterprise-grade racks, a dedicated server room, and a budget that belongs in a data center. But Zero had a different idea — one that starts with five compact single-board servers sitting on a desk and ends with a 56Gbps InfiniBand switch connecting them all into a unified computing cluster.

This is Part 1 of that journey: the unboxing, the hardware selection, the assembly, and the first successful boot of all five nodes. No results yet — but the foundation is extraordinary.

What Is ZimaBoard 2, and Why Does It Matter for This Build?

Before diving into the cluster setup, it is worth understanding why Zero chose ZimaBoard 2 as the foundation for this experiment.

ZimaBoard 2 is a single-board server (SBS) — a category distinct from the more familiar single-board computer (SBC) like Raspberry Pi. While both are compact and low-power, the SBS designation signals a different design philosophy: these devices are built to run as servers, not just as hobbyist computers. ZimaBoard 2 is developed by IceWhale Technology and is capable of running ZimaOS, TrueNAS, Proxmox, Debian, pfSense, and more.

What sets ZimaBoard 2 apart from most mini computers on the market — and what made it the centerpiece of this home server experiment — is its native PCIe 3.0 ×4 slot. As Zero explains:

"Most small computers don't come with a PCIe slot. But ZimaBoard has one by default. That's what makes this experiment possible."

This slot enables the installation of 10G NICs, NVMe adapters, GPUs, and — critically for this project — high-speed InfiniBand network cards. Combined with dual 2.5G Ethernet built-in, ZimaBoard 2 offers a level of expandability that is genuinely rare at its price point.
Additional specs relevant to this build:

• Native SATA support for 2.5" HDDs/SSDs (no adapter hats required)
• Low power consumption — ideal for 24/7 home server operation
• Silent, fanless-friendly design
• Small form factor that fits inside a standard rack with the right mounting solution

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The Vision: A DIY Supercomputer Using 5 Home Server Nodes

Zero's concept is straightforward in theory and ambitious in practice: connect five ZimaBoard 2 units via high-speed networking so that their combined compute resources can be treated as a single, unified system — a classic high-performance computing (HPC) cluster architecture.

This is not a new idea. Supercomputers have long been built by linking many smaller nodes together. What is new here is the price point and the form factor. Zero had previously attempted a similar experiment using four Lichee RV Nano computers, but concluded that ZimaBoard 2 offered a higher probability of success:

"When I thought about it more carefully, I realized this could work even better. The specs are higher, and the PCIe slot is already there. The success rate is higher than with the tiny computers I used before."

IceWhale Technology, the maker of ZimaBoard 2, agreed to sponsor the hardware — providing five complete units along with their accessory kits. Zero is clear that no money changed hands; the arrangement was a product provision for the purposes of this experiment.

Hardware Overview: Everything Used in This Build

1. Five ZimaBoard 2 Units

Each unit arrived in identical packaging with the same specification. Zero notes that the board itself is only the top portion of the assembled unit — the lower section is a hard drive rack and mounting chassis. Each kit included:

• The ZimaBoard 2 board
• PCIe extension cable
• Screw kit and PCIe bracket
• Hard drive rack

Assembly was completed for all five units. One hard drive was installed per unit — not for storage use, but because the ZimaBoard 2 case requires a drive to be present for the PCIe bracket to mount correctly.

2. Mellanox ConnectX-3 Pro FDR InfiniBand Cards (×5)

This is where the build moves decisively into professional territory. Zero selected the Mellanox ConnectX-3 Pro FDR InfiniBand card — a PCIe network adapter capable of:

• Up to 40GbE (40 Gigabit Ethernet) over standard Ethernet protocols
• Up to 56Gbps using FDR InfiniBand (Fourteen Data Rate) protocol

The card uses a QSFP+ port (Quad Small Form-factor Pluggable Plus) — a connector type typically found only in data centers and enterprise server environments.

A key feature of the ConnectX-3 Pro is RDMA (Remote Direct Memory Access) support, which allows data to be transferred between systems without burdening the CPU. As Zero explains:

"Apparently, this card can handle data communication without putting load on the CPU. That's what enables data exchange at an extraordinary speed."

The practical limitation: ZimaBoard 2's PCIe slot is ×4, while the ConnectX-3 Pro is natively a ×8 card. This means the card physically overhangs the slot slightly, and the maximum throughput is capped at approximately 32Gbps on ZimaBoard 2 — still more than three times the speed of a 10GbE connection, and entirely sufficient for this experiment.

"Even at 32Gbps, it's faster than 10G LAN. And it's a card I can use for future projects too — so I'm treating it as an investment."

3. Custom-Manufactured 56Gbps QSFP+ DAC Cables (×5)

Standard QSFP+ cables at 0.5m length are either unavailable or prohibitively expensive on the consumer market. Zero's solution: have them custom-manufactured.
The cables are DAC (Direct Attach Copper) cables — passive copper cables that carry high-speed signals between QSFP+ ports without requiring optical transceivers. For distances under 1 meter, copper DAC cables are both cost-effective and fully capable of handling 56Gbps throughput.
Each cable was tested and verified at 56Gbps before delivery. Zero notes they even carry a custom logo — a small but satisfying touch for a project of this scale.

"If anyone wants one, let me know in the comments. I might be able to arrange manufacturing — though I'm not sure who would actually want one."

4. Mellanox SX6036 InfiniBand Switch

Connecting five nodes in a cluster requires more than point-to-point cables. A switch is needed so that all nodes can communicate with each other simultaneously — the equivalent of a network hub, but for InfiniBand.
Zero selected the Mellanox SX6036, a 36-port QSFP+ InfiniBand switch designed for enterprise and HPC environments. Key specifications:

• 36 QSFP+ ports — more than enough for five nodes, with room to expand
• Full 56Gbps FDR InfiniBand support on all ports
• Managed switch with its own configuration interface

The SX6036 is a rack-mounted unit and noticeably large compared to the ZimaBoard 2 nodes. Zero acknowledges the contrast:

"It's huge. It's not something you'd normally put on a desk. But it's a server-grade piece of equipment, so that's expected."

All components in the network path — the cards, the cables, and the switch — are rated for 56Gbps, ensuring no bottleneck is introduced by the interconnect layer. The effective ceiling remains ZimaBoard 2's PCIe ×4 interface at ~32Gbps per node.

5. Enterprise LAN Switch (48-Port)

To keep management traffic and InfiniBand data traffic separate, Zero also deployed a 48-port enterprise LAN switch for standard Ethernet connectivity. Each ZimaBoard 2 connects to this switch via its built-in 2.5G Ethernet port, providing internet access and standard network management — completely independent of the InfiniBand cluster network.

Assembly and First Boot: What Happened

With all hardware assembled and cabled, Zero powered on the system. The sequence:

1. Mellanox SX6036 switch powered on — immediately loud due to high-speed cooling fans
2. All five ZimaBoard 2 units powered on — PCIe slots illuminated, indicating card recognition
3. LAN switch connected to upstream internet source
4. Network scan performed — all five ZimaBoard 2 units appeared on the network

"They're showing up. One, two, three, four — and there's Chappy, the AI unit from last time. Five total. All alive."

Zero then logged into one unit via tablet, confirming the ZimaOS welcome screen and successful boot. A check of the network interfaces showed the Mellanox card was recognized at the hardware level (listed under Mellanox Technologies), but no driver was loaded — expected behavior, as ZimaOS does not include InfiniBand drivers by default.

"The PCIe cards are alive and receiving power. But the OS doesn't have the Mellanox driver built in, so it can't load yet. That's something we'll address in the next video when we actually attempt the cluster connection."

What Comes Next

This was Part 1: hardware acquisition, assembly, and basic boot verification. The work ahead includes:

• Installing InfiniBand drivers on all five ZimaBoard 2 nodes
• Configuring the Mellanox SX6036 switch (which requires its own setup process)
• Mounting everything in a server rack — Zero has already designed a 3D-printable bracket but has not yet printed it
• Running actual cluster benchmarks to measure combined compute performance
• Testing real workloads — the community is invited to suggest experiments in the comments

Zero is also candid about the economics of the build:

"ZimaBoard 2 itself isn't extremely expensive. When you factor in expandability and build quality, the price is reasonable. It's a bit much for a toy, but for an experiment, it's a fair price."

Why ZimaBoard 2 Is the Right Foundation for a Home Server Cluster

This project illustrates something important about ZimaBoard 2's design philosophy. Most mini computers — even capable ones — are closed systems. They run well as standalone home server nodes, but they cannot be meaningfully expanded or interconnected at the hardware level.
ZimaBoard 2 breaks that ceiling. The native PCIe slot is not a marketing feature — it is a genuine architectural decision that enables real expandability: 10G NICs, NVMe storage, GPU acceleration, and, as this project demonstrates, enterprise-grade InfiniBand interconnects.
Whether you are running Plex, Pi-hole, Proxmox, or building a home server cluster that rivals a small data center, ZimaBoard 2 is designed to grow with your ambitions. Small, hackable, and — as Zero put it — "looks like a toy but runs like a beast."

Follow Zero's DIY Supercomputer Journey

Zero's home supercomputer project is one of the most technically ambitious DIY home server builds we have seen built around ZimaBoard 2. In Part 1 alone, the hardware stack includes five ZimaBoard 2 nodes, five Mellanox ConnectX-3 Pro InfiniBand cards, five custom 56Gbps DAC cables, a 36-port Mellanox SX6036 switch, and a 48-port enterprise LAN switch.
Everything booted. Everything was recognized. The foundation is solid.
We at Zima are proud to have supported this experiment and look forward to sharing the results as Zero works toward a fully operational cluster. Subscribe to Zero's channel to follow the journey, and stay tuned to the Zima blog for further coverage.