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NVIDIA · Official-source model record

NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16

Nemotron

Listed by publisherChecked Oct 23, 2026
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Publisher-sourced inventory. Specifications come from official documentation and model cards. “Not documented” means we have no verified value. This inventory is separate from our editorial reviews.

Coverage & sources ↗

Current catalog answers

What to know about NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16

AI-compiled from linked model documentation. This is a catalog reference, not an independent performance review. Catalog checked October 23, 2026.

Which NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 does this page describe?

NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 is a model record from NVIDIA in the Nemotron family. Source

A separate version identifier is not documented in this record; the model name alone does not establish which snapshot a service runs.

How can you access NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16?

The catalog documents Open weights access for NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16. Source

As of the catalog check, this version was listed without confirmed general availability. Source

Open weights means the model weights are distributed for use under their stated terms. It does not establish a hosted API, an open-source license, or a hardware requirement.

What are NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16's context and output limits?

The documented context window is 1,000,000 tokens. Source

A separate maximum-output value is not established in this record. The context or input figure should not be used as an output allowance.

Context, input and output limits describe different constraints. Do not add the figures together to infer a larger window. Check the endpoint's accounting for conversation history, system instructions, tools, media and generated tokens; a documented maximum is not a guarantee of answer quality or a measured usable capacity.

What dates are documented for NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16?

Release date: June 4, 2026. Source This is a release milestone, not a knowledge or training cutoff.

Neither a knowledge cutoff nor a training-data cutoff is established here. A release date, repository upload or filename cannot supply those missing dates.

What can NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 receive and generate?

Documented inputs: text. Source

Documented outputs: text. Source

Input support and output generation are separate capabilities. Reading an image does not establish image generation; a text output listing does not establish speech output. File sizes, formats and media limits depend on the documented implementation.

What license is recorded for NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16?

The recorded license label is openmdw-1.1. Source

Read the linked license and associated use terms for this exact version before redistribution, commercial deployment or fine-tuning. A label alone does not establish every permission, restriction or obligation, and it does not determine the terms of a separate hosted service.

What is documented about the NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 checkpoint?

This evidence refers to nvidia/NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 at recorded revision 77df655d5e9f8362164ed14dd8b48f8bce657498, checked October 23, 2026. Repository metadata

Safetensors metadata records 560,524,578,816 stored parameters. This is a stored-weight count, not necessarily the number activated per token, a download size or a GPU-memory requirement. Repository metadata

Recorded architecture class: NemotronHForCausalLM. Repository metadata

Repository task tag: text-generation. A task tag identifies a distribution category; it does not measure performance on that task. Repository metadata

Listed library: transformers. Check that library's version and model support before loading the weights. Repository metadata

Repository language labels: en, fr, es, it, de, pt, ja, ko, hi, ar, zh, and he. These labels are not independent evaluations of language quality. Repository metadata

Repository access gate: false. This records the repository's gate setting when checked; licensing and use terms still apply. Repository metadata

What the configuration file says

The pinned config.json contains these values. Pinned configuration

max_position_embeddings
262,144
torch_dtype
bfloat16
num_attention_heads
64
num_key_value_heads
2
hidden_size
8,192

Configuration values describe the checkpoint and its implementation. In particular, max_position_embeddings, sliding_window and rope_scaling do not independently establish an API context limit, tested usable length or hardware requirement. Runtime, quantization, cache, batch size and input length affect deployment behavior.

Read the retrieved model card for setup and qualifications. Model card

Keep the exact version in view

Other Nemotron models from NVIDIA.

These are separate records in the same publisher family. A shared family name does not establish equal capabilities or interchangeable licenses.

The documented record

Specifications, with their sources.

A missing value remains unknown. Input limits, output limits and the total context window are separate measurements.

Publisher
NVIDIASource ↗
Family
NemotronSource ↗
Version
Not documented
Availability
Listed by publisherSource ↗
Access
Open weightsSource ↗
Inputs
TextSource ↗
Outputs
TextSource ↗
Context window
1,000,000 tokensSource ↗
Maximum input
Not documented
Maximum output
Not documented
Knowledge cutoff
Not documented
Training-data cutoff
Not documented
Training completed
Not documented
Release date
Jun 4, 2026Release date · day precisionSource ↗
License
openmdw-1.1Source ↗
Input price / 1M tokens
Not documented
Output price / 1M tokens
Not documented

Read this with the numbers.

Official publisher model repository; listed status confirms a catalog entry, not a verified hosted API service. Context is the publisher’s nominal 1M token figure (K/M normalized decimally), not a tested request limit. Pretraining and post-training data have distinct cutoffs; no single combined cutoff is asserted. Publisher repository evidence (2026-10-23): Publisher task label: text-generation. Published architecture metadata: NemotronHForCausalLM. Repository library label: transformers. Model-card language labels: en, fr, es, it, de, pt, ja, ko, hi, ar, zh, he; these labels are not evaluated proficiency scores. Published safetensors metadata counts 560,524,578,816 stored parameters; this is not an active-parameter count for mixture-of-experts models. Published configuration: max_position_embeddings=262144; dtype=bfloat16. Checkpoint configuration is not a verified hosted serving limit; context and output limits remain separate documented fields.

Model identifiers and aliases 1
  • nvidia/NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16

Follow the evidence

Official sources.

  1. NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16 — official model card ↗huggingface.co
  2. NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16: official publisher repository metadata ↗huggingface.co
  3. NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16: publisher model card at revision 77df655d5e9f ↗huggingface.co
  4. NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16: published checkpoint configuration at revision 77df655d5e9f ↗huggingface.co

From the Headless Thrones newsroom

Editorial about NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16

No published articles are linked to this exact model yet. New coverage will appear here as it is published.

Your starting point

NVIDIA-Nemotron-3-Ultra-550B-A55B-BF16

NVIDIA · Open weights

Browse all models ↗
Inputs
TextSource ↗
Outputs
TextSource ↗
Context window
1,000,000 tokensSource ↗
Knowledge cutoff
Not documented

A place to begin comparing

1,124 models to consider.

Matches must share an access route, support every documented input type of your starting model, and return text. When both publish a context limit in the same field, the candidate must fall between half and twice that limit. Unknown or differently defined limits remain as broader matches, after verified near-context matches. Within each group, recent documented releases appear first. These criteria do not establish equal quality. The full current inventory is considered.

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Text input; text output · Shared access: Open weights · Documented context within ½–2×

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Text input; text output · Shared access: Open weights · Documented context within ½–2×

Mistral AI

Mistral Large 4

Text input; text output · Shared access: Open weights · Documented context within ½–2×

NVIDIA

NVIDIA-Nemotron-Labs-Teacher-Chat

Text input; text output · Shared access: Open weights · Documented context within ½–2×

NVIDIA

NVIDIA-Nemotron-Labs-Teacher-STEM

Text input; text output · Shared access: Open weights · Documented context within ½–2×

MiniMax

MiniMax-M3

Text input; text output · Shared access: Open weights · Documented context within ½–2×

Meta

Llama 4 Maverick 17B 128E

Text input; text output · Shared access: Open weights · Documented context within ½–2×

A record you can follow

The source belongs beside the fact.

Official sources

Model records cite the developer’s documentation, release notes and model cards. A listing alone is not a tested service or a recommendation.

Dates mean different things

Knowledge cutoff, training-data cutoff, training completion and release date are separate fields. A model’s name or repository upload date does not establish any of them.

Limits need context

Some publishers use rounded K/M token figures. Deployment, reasoning settings and regional access can change usable limits. Read the source before choosing.

Coverage and last check

Independent editorial model library assembled from primary vendor documentation and official publisher model cards. This is a dated, auditable inventory of the sources reviewed, not a claim to every model worldwide. First-party language-model inventory for OpenAI, Anthropic, Google Gemini/Gemma, xAI, Meta and Reflection. Includes vendor-listed legacy/retired identities with explicit statuses; official pretrained and instruction-tuned checkpoints remain distinct. Excludes embeddings, moderation/guard models, image/audio/video-only generation, community fine-tunes, speculative draft helpers, format/runtime/quantization duplicates, and PaliGemma dataset-specific benchmark fine-tunes. Availability means documented vendor API or downloadable official weights, not guaranteed account eligibility. Unknown specifications and dates remain null. Rounded K/M limits preserve vendor granularity; exact integers are used only where documented. No OpenRouter facts are used. Primary-source inventory of language-capable models from Alibaba/Qwen, DeepSeek, Moonshot, MiniMax, Z.ai, ByteDance Seed, Tencent, Baidu, Xiaomi, StepFun, 01.AI, Shanghai AI Laboratory, Baichuan and OpenBMB. Includes full reachable official public weight inventories plus documented hosted API models and explicit retirements. Embeddings, reward/classifier/router/tokenizer/draft-head components, standalone OCR/document converters and image/video/audio-only generators are excluded; multimodal language models retained. Official packaging variants are folded into aliases where a canonical listing was identifiable; remaining research/base/SFT variants retain exact identities. Not a guarantee every historical/private/regional model is available. Unknown specifications remain null; K/M API display quantities use decimal normalization where explicitly noted, rather than implying verified exact serving ceilings. Model-name dates and repository creation timestamps are never used as release/training dates. Open weights does not mean unrestricted or OSI-open-source licensing. Some model-card bodies were unreachable; their public inventory metadata is retained and disclosed. Official Mistral, Cohere, AI21, NVIDIA Nemotron, Microsoft Phi/MAI, Amazon Nova, IBM Granite, AllenAI OLMo/Molmo, TII Falcon, Nous Research, Arcee and Essential AI model inventory checked 2026-10-23. Includes base, instruction, reasoning, coding and text-producing multimodal models, including legacy API versions. Excludes embeddings/rerankers/reward and safety classifiers, image/audio/video-only generation, robotics-only models, duplicate quantization/runtime packages, adapters, intermediate checkpoint experiments, and third-party mirrors. Arcee coverage focuses on its named product families rather than exploratory merge repositories. Repository listing means listed, not independently verified API availability. K/M figures are nominal decimal normalizations when the source supplies shorthand; deployment-specific exact token limits may differ. Unverified values remain null. This is a source-backed inventory, not a complete claim-level independent editorial review. Supplemental official Liquid AI, Reka and Inception generative language catalog. Excludes media-only generators and decision/classification-only models. No assumed training dates.

Catalog edition updated . Source links are provided on each model record.

View the full coverage report and discovery sources ↗