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Nvidia Nemotron 3 Ultra 550B Thinking

Added Jun 4, 2026Open weights

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Nvidia's Nemotron 3 Ultra 550B A55B model from the Nemotron 3 family. It uses a hybrid Mamba-Transformer MoE architecture. Provider-specific context limits vary, with the longest current route supporting up to 1M context. Thinking enabled.

  • Reasoning
  • Tools
  • Parallel tools
Input
Text
Output
Text
Discovery tier
Open weights

Pricing

USD per 1M tokens
Input
$0.50
Output
$2.50

Reference prices as published by the model provider. API example

Specifications

Context window
1M
Max output
65.5K
Average output (7 days)
654 tokens
Longer than 58% of 468 models

Side by side

Nvidia Nemotron 3 Ultra 550B Thinking compared

Specifications, prices, speed and benchmark scores next to each other. Benchmarks below show every compared model too.

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Nvidia Nemotron 3 Ultra 550B ThinkingnvidiaThis modelGPT 5OpenAIRemove
ProvidernvidiaOpenAI
Discovery tierOpen weightsFrontier
AddedJun 4, 2026Aug 7, 2025
Limits
Context window1MBest400K
Max output65.54K128KBest
Average output654 tokens411 tokens
Pricing, USD per 1M tokens
Input$0.50Best$1.25
Output$2.50Best$10.00
Cache read—$0.13
Performance
Throughput79.0 tok/s—
Time to first token2.1 s—
Request success (24h)99.7%—
Benchmark indexes
Intelligence Index22.923.0Best
Coding Index49.3Best37.8
Math Index—94.3
Capabilities
ReasoningYesYes
ToolsYesYes
VisionNoYes
Structured outputNoYes
PDF inputNoYes
Parallel toolsYesNo
Reasoning effort—minimal, low, medium, high

Public evaluations

Benchmarks

Independent evaluation results, with how each score ranks among the models in the Noumen catalog.

  • Nvidia Nemotron 3 Ultra 550B Thinking
  • GPT 5

Intelligence Index

  • Nvidia Nemotron 3 Ultra 550B Thinking22.9
  • GPT 523.0

Nvidia Nemotron 3 Ultra 550B Thinking: Better than 56% of 326 scored models

3.8Catalog models by score55.1

Indexes

  • Coding Index

    Composite of the coding evaluations

    • Nvidia Nemotron 3 Ultra 550B Thinking: 49.3Top
    • GPT 5: 37.8

  • Math Index

    Composite of the math evaluations

    • Nvidia Nemotron 3 Ultra 550B Thinking: —
    • GPT 5: 94.3

Agentic work

  • AutomationBench-AA

    Workflow automation, penalized for guardrail violations

    • Nvidia Nemotron 3 Ultra 550B Thinking: 3.0%
    • GPT 5: —

  • AutomationBench-AA tasks completed

    Workflows finished end to end without a guardrail violation

    • Nvidia Nemotron 3 Ultra 550B Thinking: 0.3%
    • GPT 5: —

  • AA-Briefcasev1.1

    Agentic knowledge work, rated head to head

    • Nvidia Nemotron 3 Ultra 550B Thinking: 876 Elo
    • GPT 5: —

  • GDPval-AAv2.1

    Economically valuable occupational tasks, rated head to head

    • Nvidia Nemotron 3 Ultra 550B Thinking: 1,013 EloTop
    • GPT 5: 918 Elo

Document reasoning

  • GDP.pdf

    Professional reasoning over PDF documents, all-pass rate

    • Nvidia Nemotron 3 Ultra 550B Thinking: 5.0%
    • GPT 5: —

  • AA-LCRv1.1

    Reasoning across long documents

    • Nvidia Nemotron 3 Ultra 550B Thinking: 79.3%Top
    • GPT 5: 78.2%

  • MLCR-AA

    Long-context reasoning over medical records

    • Nvidia Nemotron 3 Ultra 550B Thinking: 5.6%
    • GPT 5: —

Reasoning and knowledge

  • Humanity’s Last Exam

    Expert-level questions across academic fields

    • Nvidia Nemotron 3 Ultra 550B Thinking: 28.4%
    • GPT 5: 28.5%Top

  • GPQA Diamond

    Graduate-level science questions

    • Nvidia Nemotron 3 Ultra 550B Thinking: 86.7%Top
    • GPT 5: 85.4%

  • MMLU-Pro

    Multi-subject knowledge and reasoning

    • Nvidia Nemotron 3 Ultra 550B Thinking: —
    • GPT 5: 87.1%

  • IFBench

    Following precise output instructions

    • Nvidia Nemotron 3 Ultra 550B Thinking: 81.4%Top
    • GPT 5: 73.1%

Coding

  • Terminal-Benchv4.0

    Practical software engineering in a terminal

    • Nvidia Nemotron 3 Ultra 550B Thinking: 0.5%
    • GPT 5: —

  • SciCode

    Scientific computing in Python

    • Nvidia Nemotron 3 Ultra 550B Thinking: 40.3%
    • GPT 5: —

  • LiveCodeBench

    Recent competitive programming problems

    • Nvidia Nemotron 3 Ultra 550B Thinking: —
    • GPT 5: 84.6%

Math

  • AIME 2025

    Competition mathematics, 2025 problems

    • Nvidia Nemotron 3 Ultra 550B Thinking: —
    • GPT 5: 94.3%

  • AIME

    Competition mathematics

    • Nvidia Nemotron 3 Ultra 550B Thinking: —
    • GPT 5: 95.7%

  • MATH-500

    Competition math problems

    • Nvidia Nemotron 3 Ultra 550B Thinking: —
    • GPT 5: 99.4%

Legacy evaluations

  • Terminal-Bench Hard

    Earlier terminal task suite

    • Nvidia Nemotron 3 Ultra 550B Thinking: 36.4%Top
    • GPT 5: 32.6%

  • τ²-Bench Telecom

    Tool use in a customer-support simulation

    • Nvidia Nemotron 3 Ultra 550B Thinking: 83.3%
    • GPT 5: 84.8%Top

  • AA-LCR (unversioned)

    Long-context reasoning, earlier grading

    • Nvidia Nemotron 3 Ultra 550B Thinking: 79.3%Top
    • GPT 5: 78.2%

Scores from Artificial Analysis, updated Oct 26, 2026. Artificial Analysis

Live routing data

Performance and reliability

Recent averages across requests routed for this model. Your own speed depends on prompt length, reasoning effort and load.

Throughput
79.0 tok/s
Faster than 52% of 254 models
Time to first token
2.1 s
Quicker than 75% of 254 models
Prompt cache hits
17.9%
Request success (24h)
99.7%
Reliable

Cache hits are the share of input tokens recently served from a prompt cache across all requests. They are not a forecast of your own hit rate.

Hourly request success · last 72 hoursLowest hour 85.7%
  • Healthy (98% or more)
  • Degraded (90–98%)
  • Down (under 90%)
  • No requests

Developers

Use it through the API

Noumen’s API is OpenAI-compatible: any Chat Completions client works with a base URL and a key.

Read the quickstart
curl https://www.noumen.xyz/api/v1/chat/completions \
  -H "Authorization: Bearer $NOUMEN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nvidia/nemotron-3-ultra-550b-a55b:thinking",
    "messages": [{ "role": "user", "content": "Explain this stack trace." }]
  }'
import os
from openai import OpenAI

client = OpenAI(base_url="https://www.noumen.xyz/api/v1", api_key=os.environ["NOUMEN_API_KEY"])
reply = client.chat.completions.create(
    model="nvidia/nemotron-3-ultra-550b-a55b:thinking",
    messages=[{"role": "user", "content": "Explain this stack trace."}],
)
print(reply.choices[0].message.content)

nvidia

Other nvidia models, starting with the same family.