Batch & HPC
Elastic Fabric Adapter (EFA) vs InfiniBand on Azure HPC and GPU VMs
AWS Elastic Fabric Adapter (EFA) maps to InfiniBand on Azure H-series and ND-series VMs.
Both give OS-bypass, RDMA-class networking for MPI and NCCL, but the technologies differ.
Side-by-side comparison
| Aspect | Amazon Web Services | Microsoft Azure |
|---|---|---|
| Service | Elastic Fabric Adapter (EFA) | InfiniBand on Azure HPC and GPU VMs |
| Lifecycle | Generally available | Generally available |
| What it is | An OS-bypass network interface (SRD protocol) for MPI and NCCL traffic on supported instance types. | RDMA-capable InfiniBand on H-series (HB, HX) and ND-series VMs for MPI and NCCL. It works within a scale set or availability set. |
| Pricing model | No extra charge for EFA. It comes with supported instance types. | No separate charge. InfiniBand is included in the price of RDMA-capable sizes. |
| Docs | Elastic Fabric Adapter (EFA) docs | InfiniBand on Azure HPC and GPU VMs docs |
| Pricing page | Elastic Fabric Adapter (EFA) pricing | InfiniBand on Azure HPC and GPU VMs pricing |
| Exams | SAP-C02 Retiring | AZ-305 |
Key differences
- Technology. EFA is AWS's own Ethernet-based fabric using the SRD protocol through libfabric. Azure uses NVIDIA (Mellanox) InfiniBand, with standard verbs, UCX, or HPC-X MPI stacks.
- Scope. EFA works on many supported instance types (HPC, GPU, and some general purpose) within a subnet or AZ, usually with cluster placement groups. Azure InfiniBand is available only on RDMA-capable H- and ND-series sizes, within one scale set or availability set.
Pricing summary
Pricing models only. No prices are quoted because they change by region and over time.
- AWS
- No extra charge for EFA. It comes with supported instance types. Elastic Fabric Adapter (EFA) pricing →
- Azure
- No separate charge. InfiniBand is included in the price of RDMA-capable sizes. InfiniBand on Azure HPC and GPU VMs pricing →
Certification exam mapping
| Exam | Provider | Level | Status |
|---|---|---|---|
| AWS Certified Solutions Architect – Professional SAP-C02 | AWS | Professional | retiring Being updated to SAP-C03. Registration for SAP-C03 opens Oct 27, 2026. Last day to take SAP-C02 is Nov 16, 2026. |
| Microsoft Certified – Azure Solutions Architect Expert AZ-305 | Azure | Expert | current English version updated Apr 17, 2026. |
Relevance is based on each exam's published scope, not a line-by-line objective match. Check the official study guide.
FAQ
What is the Azure equivalent of Elastic Fabric Adapter (EFA)?
AWS Elastic Fabric Adapter (EFA) maps to InfiniBand on Azure H-series and ND-series VMs. Both give OS-bypass, RDMA-class networking for MPI and NCCL, but the technologies differ.
How does pricing compare between Elastic Fabric Adapter (EFA) and InfiniBand on Azure HPC and GPU VMs?
AWS: No extra charge for EFA. It comes with supported instance types. Azure: No separate charge. InfiniBand is included in the price of RDMA-capable sizes. Check the official pricing pages for current rates.
Which certification exams cover this topic?
AWS Certified Solutions Architect – Professional (SAP-C02) [retiring]; Microsoft Certified – Azure Solutions Architect Expert (AZ-305).