SXM (socket)
lastmod 2025-06-11created 2025-06-111 edits
SXM is a high-bandwidth socket solution for connecting NVIDIA compute accelerators to a system.
Each NVIDIA Tesla generation since the P100 model, the DGX computer series, and HGX boards come with an SXM socket type that delivers high bandwidth, power delivery, and more, and is used for the corresponding GPU daughter cards.
A100 40GB PCIe vs A100 SXM4
- NVIDIA A100 PCIe vs SXM4 Comparison and Use Cases in 2024 — Blog — DataCrunch
- Differences between a100 sxm and a100 pcie | SharedIT - IT knowledge sharing network
Key specification comparison
| Category | A100 PCIe | A100 SXM4 |
| Form factor | PCIe card | SXM module |
| Memory bandwidth | 1,935 GB/s | 2,039 GB/s |
| Maximum power consumption | 250W | 400W |
| GPU memory | 40GB | 40GB or 80GB |
| Interconnect | PCIe Gen4 64GB/s | NVLink 600GB/s |
Performance difference
SXM GPUs offer higher memory bandwidth (2,039 GB/s vs 1,935 GB/s) and a higher TDP, allowing more intensive compute workloads without thermal throttling.
MLPerf benchmark results
- For BERT-Large training, SXM4 is nearly 2x faster than PCIe
- For vision models such as ResNet and Mask R-CNN, the performance difference is relatively small
Recommendations by use case
- When SXM4 is better
- Large-scale ML model training
- Multi-GPU configurations (up to 8 GPUs connected)
- Inference workloads requiring high throughput
- Long-running continuous workloads
- Flexible installation in existing servers
- Relatively lower power consumption (250W vs 400W)
- Cost-effective single-GPU configurations
- General development/test environments
Practical considerations
- Power and cooling: at 400W, SXM4 needs more power and an advanced cooling system
- Scalability: SXM4 allows direct GPU-to-GPU communication via NVLink (600GB/s)
- Price: the PCIe version is generally cheaper
- Installation: PCIe installs easily in standard servers; SXM4 requires a dedicated system
So for large-scale AI training or uses where high performance matters, choose SXM4;
for general development or when cost is a concern, the PCIe version is the better choice.