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AI Choice Engine

Model comparison

NVIDIA Nemotron 3 Ultra vs Step 5 Preview

NVIDIA against StepFun, compared on context, price, and verified benchmark results.

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

NVIDIA

NVIDIA Nemotron 3 Ultra

Frontier · Open weights

vs

StepFun

Step 5 Preview

Frontier

AI model capability comparison
SpecificationNVIDIA Nemotron 3 UltraStep 5 Preview
ProviderNVIDIAStepFun
TierFrontierFrontier
Context window1M1M
Max outputNot verifiedUnverifiedNot verifiedUnverified
Input / 1M tokensWinner: $0.50$1
Output / 1M tokensWinner: $2.20$2.70
WeightsOpenClosed
Parameters550B total / 55B active (MoE)600B total / 27B active MoE (StepFun)
Reasoning levelslow, high, maxNot verifiedUnverified
Modalitiestexttext, image
API model idnemotron-3-ultra-550b-a55bstep-5-preview
ReleasedJune 4, 2026September 18, 2026
Artificial Analysis Intelligence Index (2026-09-26)22.9Winner: 43.7

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

  • 2026-09-26
    Artificial Analysis

    Composite index blending reasoning, knowledge, and coding evals into one 0–100 score.

    Comparable with caveatOnly same-version scores are comparable. v4.3.2 was rebaselined (the top score fell from 66 on v4.1.1 to ~58), so v4.1.1 figures must not be compared with v4.3.2 figures — check measuredAt.

Pricing tiers

NVIDIA Nemotron 3 Ultra: Open weights (weights + data + recipes); $0.50/$2.20 per MTok is the third-party hosted rate (OpenRouter; hosts report cached input $0.10, 262K served context and 16,384 output — secondary). 550B/55B MoE, 1M native context.

Step 5 Preview: $1.00/$2.70 per MTok on the StepFun platform (cache-hit input $0.05); StepFun lists it under Multimodal Reasoning Models and says output tokens include reasoning. No max-output figure is published. StepFun says open weights follow on 2026-10-15. Release date per Artificial Analysis's listing (StepFun's launch page is undated).

FrontierOpen weightsRecord checked September 26, 2026

NVIDIA Nemotron 3 Ultra

Nemotron 3 Ultra is NVIDIA's open-weight (550B/55B) frontier MoE with a 1M-token context.

Best for

  • Open-weight frontier
  • Self-hosting on NVIDIA GPUs
  • Reasoning

Watch out

Top US open-weight until Thinking Machines Inkling; verify hosted pricing.

FrontierRecord checked September 26, 2026

Step 5 Preview

Step 5 Preview is StepFun's new frontier reasoning model — a 1M-context, vision-input API preview that lands near Kimi K3 and GLM 5.3 on the Artificial Analysis index at a lower price.

Best for

  • Long-context work on a budget
  • Chinese + English
  • Early testing before the open-weight drop

Watch out

Preview: weights are promised for 2026-10-15 but not yet released, and its max output is unpublished and the launch benchmarks are vendor-run.

When the cheaper one wins

NVIDIA Nemotron 3 Ultra is cheaper on output at $2.20 per million tokens against $2.70 for Step 5 Preview — about 1.2×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

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Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 3/5 core specs verified on both sides — Not published for at least one side: max output, reasoning levels.
  • 1 shared named benchmark with differing scores — Measured on: Artificial Analysis Intelligence Index.
  • Verified within the last 90 days — Newest catalog check was 2 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? NVIDIA Nemotron 3 Ultra · Step 5 Preview

Common questions

NVIDIA Nemotron 3 Ultra vs Step 5 Preview

Answered from the verified figures on this page rather than general guidance.

Is NVIDIA Nemotron 3 Ultra or Step 5 Preview cheaper for input?
NVIDIA Nemotron 3 Ultra is cheaper at $0.50 per million input tokens, against $1 for Step 5 Preview — roughly 2.0× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; NVIDIA Nemotron 3 Ultra has tiered pricing: Open weights (weights + data + recipes); $0.50/$2.20 per MTok is the third-party hosted rate (OpenRouter; hosts report cached input $0.10, 262K served context and 16,384 output — secondary). 550B/55B MoE, 1M native context. Step 5 Preview has tiered pricing: $1.00/$2.70 per MTok on the StepFun platform (cache-hit input $0.05); StepFun lists it under Multimodal Reasoning Models and says output tokens include reasoning. No max-output figure is published. StepFun says open weights follow on 2026-10-15. Release date per Artificial Analysis's listing (StepFun's launch page is undated).
Is NVIDIA Nemotron 3 Ultra or Step 5 Preview cheaper for output?
NVIDIA Nemotron 3 Ultra is cheaper at $2.20 per million output tokens, against $2.70 for Step 5 Preview — roughly 1.2× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; NVIDIA Nemotron 3 Ultra has tiered pricing: Open weights (weights + data + recipes); $0.50/$2.20 per MTok is the third-party hosted rate (OpenRouter; hosts report cached input $0.10, 262K served context and 16,384 output — secondary). 550B/55B MoE, 1M native context. Step 5 Preview has tiered pricing: $1.00/$2.70 per MTok on the StepFun platform (cache-hit input $0.05); StepFun lists it under Multimodal Reasoning Models and says output tokens include reasoning. No max-output figure is published. StepFun says open weights follow on 2026-10-15. Release date per Artificial Analysis's listing (StepFun's launch page is undated).
Which has the larger context window, NVIDIA Nemotron 3 Ultra or Step 5 Preview?
Both accept about 1M tokens of context, so document length will not decide between them.
Should I use NVIDIA Nemotron 3 Ultra or Step 5 Preview?
Both sit in the frontier tier, so the choice usually comes down to price and context rather than capability. NVIDIA Nemotron 3 Ultra suits open-weight frontier; Step 5 Preview suits long-context work on a budget.
Can I self-host NVIDIA Nemotron 3 Ultra or Step 5 Preview?
NVIDIA Nemotron 3 Ultra publishes open weights, but self-hosting and third-party provider access depend on the licence, hardware, serving support, and availability. Step 5 Preview is a closed model whose supported access paths are controlled by its provider.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: NVIDIA Nemotron 3 Ultra costs $0.50 per 1M tokens versus $1 for Step 5 Preview — a 2x difference at the headline tier.
  • Measured capability: Step 5 Preview leads Artificial Analysis Intelligence Index 43.7 to 22.9 (measured 2026-09-26).
  • Deployment: NVIDIA Nemotron 3 Ultra publishes weights you can self-host; the other is API-only.
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