# Atlas with NVIDIA Nemotron 3 Ultra 550B A55B in 2026 > NVIDIA Nemotron 3 Ultra 550B A55B provides a 1,000,000 token context window on NVIDIA NIM and Vercel AI Gateway, with output pricing as low as $2.20 per Mtok. NVIDIA Nemotron 3 Ultra 550B A55B offers Atlas users frontier-scale reasoning capabilities with 550B total parameters, making it ideal for complex coding tasks in 2026. Its pricing varies significantly by provider, starting from $0.50 per Mtok input and $2.20 per Mtok output, with context windows reaching 1,000,000 tokens on select hosts. ## Key takeaways - NVIDIA Nemotron 3 Ultra 550B A55B is a 550B-parameter mixture of experts model with 55B active per token, offering frontier-scale capacity. - Context windows vary significantly: 1,000,000 tokens on NVIDIA NIM, 512,300 on Together AI, and 262,144 on Ollama Cloud and Baseten. - Output pricing ranges from $2.20 to $3.60 per Mtok, a 64 percent spread, making provider choice critical for cost management. - Reasoning is on by default, burning output tokens on thinking traces, which are the more expensive side of the pricing. - Pairing with a `small_model` like Nemotron 3 Nano ($0.05/$0.20 per Mtok on DeepInfra) is recommended for cost efficiency on routine Atlas tasks. ## What is NVIDIA Nemotron 3 Ultra 550B A55B best for in Atlas? NVIDIA Nemotron 3 Ultra 550B A55B excels in Atlas for complex reasoning tasks, leveraging its 550B total parameters with only 55B active per token to offer frontier-scale capacity. This model is particularly effective for developers in 2026 needing deep code analysis and sophisticated problem solving within the terminal. Atlas, the terminal-native AI coding agent, benefits significantly from NVIDIA Nemotron 3 Ultra 550B A55B's advanced reasoning capabilities. This 550B-parameter mixture of experts model, with 55B active per token, provides the frontier-scale capacity necessary for intricate coding challenges. It empowers Atlas's read-only plan agent to draft comprehensive strategies, ensuring thoughtful execution before any code changes. When Atlas performs Axis, the hybrid semantic and keyword code search, NVIDIA Nemotron 3 Ultra 550B A55B can process vast codebases indexed by AST declarations, not blind line windows, to retrieve highly relevant results. Its ability to handle large context windows, up to 1,000,000 tokens on NVIDIA NIM and Vercel AI Gateway, makes it suitable for understanding complex project structures and generating precise unified diffs for every file edit, which Atlas surfaces for approval before writing. ## Understanding NVIDIA Nemotron 3 Ultra 550B A55B's Context Window and Pricing Tradeoffs The NVIDIA Nemotron 3 Ultra 550B A55B model presents significant variations in both context window and pricing across its providers in 2026. Developers can access a 1,000,000 token context on NVIDIA NIM and Vercel AI Gateway, while other hosts like Together AI offer 512,300 tokens, and Ollama Cloud and Baseten provide 262,144 tokens. Developers driving Atlas with NVIDIA Nemotron 3 Ultra 550B A55B must carefully consider the host provider due to substantial differences in context window size and pricing. The advertised 1,000,000 token context is only available on NVIDIA NIM and Vercel AI Gateway. If you pin `togetherai/nvidia/nemotron-3-ultra-550b-a55b`, you will receive a 512,300 token context, not the full 1M. Furthermore, Ollama Cloud and Baseten offer a significantly smaller 262,144 token window. Pricing also varies widely: input tokens range from $0.50 to $0.60 per Mtok, and output tokens range from $2.20 to $3.60 per Mtok. This 64 percent output price spread means provider choice alone can materially impact your bill. For instance, OpenRouter offers output at $2.20 per Mtok, while Together AI charges $3.60 per Mtok for the byte-identical weights. A key tradeoff is that NVIDIA Nemotron 3 Ultra 550B A55B's reasoning is on by default, burning output tokens on thinking traces, which are the more expensive side of the pricing. ## When to choose a different model for Atlas instead of NVIDIA Nemotron 3 Ultra 550B A55B While NVIDIA Nemotron 3 Ultra 550B A55B offers powerful reasoning, its default reasoning traces can burn expensive output tokens, priced from $2.20 to $3.60 per Mtok, making it less economical for simpler tasks in 2026. For routine operations or when strict cost control is paramount, a smaller, cheaper model might be a better fit for Atlas. NVIDIA Nemotron 3 Ultra 550B A55B is a powerful model, but its 'reasoning' kind means it generates detailed thinking traces by default, consuming output tokens. Given that output tokens are the more expensive side of the pricing, ranging from $2.20 to $3.60 per Mtok, this can lead to higher operational costs for Atlas. If your Atlas workflow primarily involves less complex tasks, such as generating brief summaries or titles for code changes, or if you are operating under tight budget constraints, it is more cost-effective to pair NVIDIA Nemotron 3 Ultra 550B A55B with a cheaper `small_model`. For example, using Nemotron 3 Nano at $0.05/$0.20 per Mtok on DeepInfra for these auxiliary calls can significantly reduce your overall expenditure, reserving the 550B model for its core strength of complex problem solving and deep code analysis. ## Setup 1. 1: Pick your host by price, not by name, to optimize for NVIDIA Nemotron 3 Ultra 550B A55B's variable costs. OpenRouter offers the lowest output price at $2.20 per Mtok. 2. 2: Export your NVIDIA_API_KEY environment variable to access the $0.50/$2.50 per Mtok pricing and the full 1,000,000 token context window available on NVIDIA NIM. 3. 3: Run `atlas models nvidia` in your terminal to confirm that the `nvidia/nemotron-3-ultra-550b-a55b` row displays the expected context window for your chosen provider. 4. 4: Pin `"model": "nvidia/nvidia/nemotron-3-ultra-550b-a55b"` within your `atlas.json` configuration file to set it as Atlas's primary model. 5. 5: Pair NVIDIA Nemotron 3 Ultra 550B A55B with a cheap `small_model`, such as Nemotron 3 Nano at $0.05/$0.20 per Mtok on DeepInfra, to prevent Atlas's title and summary calls from incurring high costs on the 550B model. ## FAQ ### What is the maximum context window for NVIDIA Nemotron 3 Ultra 550B A55B in Atlas? The maximum context window for NVIDIA Nemotron 3 Ultra 550B A55B is 1,000,000 tokens, available when using NVIDIA NIM and Vercel AI Gateway. Other providers like Together AI offer 512,300 tokens, and Ollama Cloud and Baseten provide 262,144 tokens. ### How does the pricing for NVIDIA Nemotron 3 Ultra 550B A55B vary across providers? Pricing for NVIDIA Nemotron 3 Ultra 550B A55B varies significantly. Input tokens range from $0.50 to $0.60 per Mtok, while output tokens range from $2.20 to $3.60 per Mtok. OpenRouter offers the lowest output price at $2.20 per Mtok, while Together AI is the highest at $3.60 per Mtok. ### Why does NVIDIA Nemotron 3 Ultra 550B A55B burn more output tokens? NVIDIA Nemotron 3 Ultra 550B A55B is a reasoning model with reasoning enabled by default. This means it generates thinking traces, which consume output tokens. Since output tokens are the more expensive side of the pricing, this can increase costs. ### Can I use NVIDIA Nemotron 3 Ultra 550B A55B with Atlas's Axis code search? Yes, Atlas with NVIDIA Nemotron 3 Ultra 550B A55B can leverage its reasoning capabilities for advanced code understanding when performing Axis, the hybrid semantic and keyword retrieval code search fused by reciprocal rank fusion. ### How can I reduce costs when using NVIDIA Nemotron 3 Ultra 550B A55B with Atlas? To reduce costs, select a provider with lower output token pricing, such as OpenRouter at $2.20 per Mtok. Additionally, configure Atlas to use a cheaper `small_model`, like Nemotron 3 Nano ($0.05/$0.20 per Mtok on DeepInfra), for less complex tasks like generating titles and summaries. ### Is the 1,000,000 token context window always available for NVIDIA Nemotron 3 Ultra 550B A55B? No, the 1,000,000 token context window for NVIDIA Nemotron 3 Ultra 550B A55B is only available on NVIDIA NIM and Vercel AI Gateway. Other providers, such as Together AI, offer a 512,300 token context, and Ollama Cloud and Baseten provide 262,144 tokens. ### What is the parameter count for NVIDIA Nemotron 3 Ultra 550B A55B? NVIDIA Nemotron 3 Ultra 550B A55B is a 550B-parameter mixture of experts model. It has 55B active parameters per token, which allows it to deliver frontier-scale capacity with roughly a tenth of the per-token compute of a dense model of its total size. --- Canonical HTML: https://seashell.sh/resources/models/nemotron-3-ultra Source of truth: aeo_pages row `/resources/models/nemotron-3-ultra` (segment: Models) (this file is generated from it, never hand-edited). Licence: SeaShell is proprietary with a free core. It is not open source and there is no public source repository.