Choosing the Right NVIDIA Mellanox Network Switch
NVIDIA Mellanox network switches form the backbone of modern high-performance data center fabrics. Whether building an AI training cluster, a storage network, or a general-purpose fabric, selecting the correct switch model directly impacts bandwidth, latency, and cost efficiency. This guide compares SN3700, SN3800, and SN2100.
Switch Specifications Comparison
| Specification | SN3700 | SN3800 | SN2100 |
|---|---|---|---|
| Chipset | Spectrum-3 | Spectrum-4 | Spectrum-2 |
| Max Port Speed | HDR 200Gb/s | NDR 400Gb/s | EDR 100Gb/s |
| Total Ports | 64 x HDR200 | 8 x NDR400 + 16 x HDR200 | 16 x EDR100 |
| Aggregate Throughput | 12.8 Tbps | 51.2 Tbps | 1.6 Tbps |
| Packet Buffer | 64 MB shared | 128 MB shared | 16 MB shared |
| Latency | ~130 ns | ~100 ns | ~190 ns |
| Power | 350W | 550W | 75W |
| RoCEv2 | Yes | Yes | Yes |
| InfiniBand Mode | Yes | Yes | Yes |
| Ethernet Mode | Yes | Yes | Yes |
SN3700: The Versatile 200Gb/s Workhorse
The SN3700 is the most widely deployed Mellanox switch. Its 64 HDR 200Gb/s ports make it ideal for AI training leaf/spine, storage fabrics, HPC interconnect, and general data center L2/L3 switching. Key advantage: Dual-mode operation—same switch runs InfiniBand or Ethernet.
SN3800: The 400Gb/s Next-Generation Core
The SN3800 (Spectrum-4) is designed for H100/H200 GPU infrastructure: 8 NDR 400Gb/s ports + 16 HDR 200Gb/s ports, 51.2 Tbps throughput. Key advantage: Gradual HDR-to-NDR migration without replacing the entire fabric.
SN2100: The Entry-Level 100Gb/s Edge
The SN2100 is the cost-effective choice: 16 x 100Gb/s ports, 75W power. Ideal for small AI clusters (8-16 GPUs), edge/top-of-rack, and budget-constrained projects.
Decision Matrix
| Scenario | Recommended Switch | Reason |
|---|---|---|
| AI cluster 256-1024 GPUs | SN3700 + SN3800 | HDR/NDR bisection |
| AI cluster 32-128 GPUs | SN3700 | Full HDR, cost-effective |
| AI cluster 8-16 GPUs | SN2100 | Low cost, adequate 100Gb/s |
| Storage fabric (all-flash) | SN3700 | 200Gb/s NVMe-oF |
| HPC simulation | SN3700 (InfiniBand) | Sub-us latency |
Frequently Asked Questions
Can SN3700 switch between InfiniBand and Ethernet?
Yes. All ports must run in the same mode—you cannot mix IB and Ethernet ports on one SN3700. Switch modes via firmware configuration.
Is refurbished performance identical to new?
Yes. Same Spectrum chipset, same port speeds, same buffer sizes. Refurbished SN3700 costs 40-60% less.
Browse our network switches collection for availability.