Grok 4 Fast Reasoning vs Nemotron 3 Nano Omni
Grok 4 Fast Reasoning (2025) and Nemotron 3 Nano Omni (2026) are frontier reasoning models from xAI and NVIDIA AI. Grok 4 Fast Reasoning ships a not-yet-sourced context window, while Nemotron 3 Nano Omni ships a 262K-token context window. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
Nemotron 3 Nano Omni is safer overall; choose Grok 4 Fast Reasoning when reasoning depth matters.
Decision scorecard
Local evidence first| Signal | Grok 4 Fast Reasoning | Nemotron 3 Nano Omni |
|---|---|---|
| Decision fit | General | Long context and Vision |
| Context window | — | 262K |
| Cheapest output | - | - |
| Provider routes | 1 tracked | 1 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4 Fast Reasoning uniquely exposes Reasoning in local model data.
- Nemotron 3 Nano Omni has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Nemotron 3 Nano Omni uniquely exposes Multimodal in local model data.
- Local decision data tags Nemotron 3 Nano Omni for Long context and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output prices on this page.
Grok 4 Fast Reasoning
Unavailable
No complete token price in local provider data
Nemotron 3 Nano Omni
Unavailable
No complete token price in local provider data
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Grok 4 Fast Reasoning and Nemotron 3 Nano Omni; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Reasoning before moving production traffic.
- Nemotron 3 Nano Omni adds Multimodal in local capability data.
- No overlapping tracked provider route is sourced for Nemotron 3 Nano Omni and Grok 4 Fast Reasoning; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Multimodal before moving production traffic.
- Grok 4 Fast Reasoning adds Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-09-01 | 2026-04-28 |
| Context window | — | 262K |
| Parameters | — | 30B |
| Architecture | decoder only | Hybrid Mamba-Transformer MoE |
| License | Proprietary | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4 Fast Reasoning | Nemotron 3 Nano Omni |
|---|---|---|
| Input price | - | - |
| Output price | - | - |
| Providers |
Pricing not yet sourced for either model.
Capabilities
| Capability | Grok 4 Fast Reasoning | Nemotron 3 Nano Omni |
|---|---|---|
| Vision | No | No |
| Multimodal | No | Yes |
| Reasoning | Yes | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | No |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on multimodal input: Nemotron 3 Nano Omni and reasoning mode: Grok 4 Fast Reasoning. Both models share the core language-model surface, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
Pricing coverage is uneven: Grok 4 Fast Reasoning has no token price sourced yet and Nemotron 3 Nano Omni has no token price sourced yet. Provider availability is 1 tracked routes versus 1. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Grok 4 Fast Reasoning when reasoning depth are central to the workload. Choose Nemotron 3 Nano Omni when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency. For teams standardizing a stack, that distinction is often the difference between a benchmark win and a reliable deployment.
FAQ
Is Grok 4 Fast Reasoning or Nemotron 3 Nano Omni open source?
Grok 4 Fast Reasoning is listed under Proprietary. Nemotron 3 Nano Omni is listed under Open Source. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for multimodal input, Grok 4 Fast Reasoning or Nemotron 3 Nano Omni?
Nemotron 3 Nano Omni has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, Grok 4 Fast Reasoning or Nemotron 3 Nano Omni?
Grok 4 Fast Reasoning has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok 4 Fast Reasoning and Nemotron 3 Nano Omni?
Grok 4 Fast Reasoning is available on Microsoft Foundry. Nemotron 3 Nano Omni is available on OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
When should I pick Grok 4 Fast Reasoning over Nemotron 3 Nano Omni?
Nemotron 3 Nano Omni is safer overall; choose Grok 4 Fast Reasoning when reasoning depth matters. If your workload also depends on reasoning depth, start with Grok 4 Fast Reasoning; if it depends on provider fit, run the same evaluation with Nemotron 3 Nano Omni.
Continue comparing
Last reviewed: 2026-05-14. Data sourced from public model cards and provider documentation.