Claude Fable 5 vs Nemotron 3 Ultra
Claude Fable 5 (2026) and Nemotron 3 Ultra (2026) are frontier-tier reasoning models from Anthropic and NVIDIA AI. Claude Fable 5 ships a 1m-token context window, while Nemotron 3 Ultra ships a 1m-token context window. On pricing, Nemotron 3 Ultra costs $0.50/1M input tokens versus $10/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Nemotron 3 Ultra is ~1900% cheaper at $0.50/1M; pay for Claude Fable 5 only for vision-heavy evaluation.
Decision scorecard
Local evidence first| Signal | Claude Fable 5 | Nemotron 3 Ultra |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps and long-context analysis |
| Decision fit | Coding, RAG, and Agents | Long context |
| Context window | 1m | 1m |
| Cheapest output | $50/1M tokens | $2.20/1M tokens |
| Provider routes | 5 tracked | 1 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Claude Fable 5 has broader tracked provider coverage for fallback and procurement flexibility.
- Claude Fable 5 uniquely exposes Vision, Multimodal, and Function calling in local model data.
- Local decision data tags Claude Fable 5 for Coding, RAG, and Agents.
- Nemotron 3 Ultra has the lower cheapest tracked output price at $2.20/1M tokens.
- Local decision data tags Nemotron 3 Ultra for Long context.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Fable 5
$20,500
Cheapest tracked route/tier: Anthropic
Nemotron 3 Ultra
$950
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $19,550. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Nemotron 3 Ultra is $47.80/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Function calling before moving production traffic.
- Provider overlap exists on OpenRouter; start route-level A/B tests there.
- Claude Fable 5 is $47.80/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Fable 5 adds Vision, Multimodal, and Function calling in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-09 | 2026-06-04 |
| Context window | 1m | 1m |
| Parameters | — | 550B |
| Architecture | Decoder Only | Mixture of Experts |
| License | Proprietary | NVIDIA Open Model |
| Openness | Proprietary | Open weights |
| Commercial use | Commercial use: conditional | Commercial use: permitted |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Claude Fable 5 | Nemotron 3 Ultra |
|---|---|---|
| Input price | $10/1M tokens | $0.50/1M tokens |
| Output price | $50/1M tokens | $2.20/1M tokens |
| Providers |
Capabilities
| Capability | Claude Fable 5 | Nemotron 3 Ultra |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Deep dive
The capability footprint differs most on vision: Claude Fable 5, multimodal input: Claude Fable 5, function calling: Claude Fable 5, tool use: Claude Fable 5, and structured outputs: Claude Fable 5. Both models share reasoning mode, 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.
For cost, Claude Fable 5 lists $10/1M input and $50/1M output tokens on the cheapest tracked provider, while Nemotron 3 Ultra lists $0.50/1M input and $2.20/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Nemotron 3 Ultra lower by about $20.99 per million blended tokens. Availability is 5 providers versus 1, so concentration risk also matters.
Choose Claude Fable 5 when vision-heavy evaluation and broader provider choice are central to the workload. Choose Nemotron 3 Ultra when provider fit and lower input-token cost 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.
FAQ
Which has a larger context window, Claude Fable 5 or Nemotron 3 Ultra?
Claude Fable 5 supports 1m tokens, while Nemotron 3 Ultra supports 1m tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Fable 5 or Nemotron 3 Ultra?
Nemotron 3 Ultra is cheaper on tracked token pricing. Claude Fable 5 costs $10/1M input and $50/1M output tokens. Nemotron 3 Ultra costs $0.50/1M input and $2.20/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Fable 5 or Nemotron 3 Ultra open source?
Claude Fable 5 is listed under Proprietary. Nemotron 3 Ultra is listed under NVIDIA Open Model. 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 vision, Claude Fable 5 or Nemotron 3 Ultra?
Claude Fable 5 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Claude Fable 5 or Nemotron 3 Ultra?
Claude Fable 5 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.
Where can I run Claude Fable 5 and Nemotron 3 Ultra?
Claude Fable 5 is available on Anthropic, AWS Bedrock, GCP Vertex AI, Microsoft Foundry, and OpenRouter. Nemotron 3 Ultra is available on OpenRouter. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-15. Data sourced from public model cards and provider documentation.