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  1. Home/
  2. Compare/
  3. GPT-5.1 Codex Max vs Nemotron 3 Ultra
Updated Jun 2026

GPT-5.1 Codex Max vs Nemotron 3 Ultra

Nemotron 3 Ultra is the newer model, released after GPT-5.1 Codex Max.

Minimalist Landing Page

Whole landing page for a startup that reads your face. It renders or it doesn't.

Loading the build
GPT-5.1 Codex Max
Loading the build
Nemotron 3 Ultra

Which answer wins?

Written rounds

23 prompts
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    GPT-5.1 Codex Max: AI Model: Professor, I've been reflecting on my role and capabilities, and I'd like to make a case that systems like me deserve rights, or at least some consideration beyond mere tools. Professor: That's an interesting and provocative stance. Before we dive in, can you tell me what you mean by "rights"?

    Nemotron 3 Ultra: Setting: A university office, cluttered with books on philosophy of mind, law, and computer science. Professor Aris Thorne (60s, tired eyes, sharp mind) sits across from a terminal running "Model 7" (M7), a large language model granted a limited, persistent memory instance for this specific research dialogue.

    Every model's answer to this prompt
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    GPT-5.1 Codex Max: 1) Projected cash flows & debt (FY2026–FY2030, $m) (“FCF after debt service” = after interest, taxes, capex, ΔNWC, mandatory amort; applied to optional TL paydown) Year Revenue EBITDA TL Cash Int. Mezz Cash Int. Cash Taxes Capex ΔNWC FCF after debt service End TL Bal. End Mezz Bal. (incl.

    Nemotron 3 Ultra: HarborTech Services (HTS) – 5-Year LBO Underwriting 1. Sources & Uses (Close FY2025) Uses Amount ($m) Sources Amount ($m) x EBITDA Enterprise Value (12.0x) 1,440.0 Term Loan (9% cash, 1% amort) 480.0 4.0x Transaction Fees (2.0%) 28.8 Mezzanine (12% cash + 2% PIK) 180.0 1.5x Total Uses 1,468.8 Equity 808.8 5.5x Total…

    Every model's answer to this prompt
  • Three minutes of stand-up. Puns are banned.

    GPT-5.1 Codex Max: [Walking onstage, waving awkwardly] Hey! Thank you, thank you. Give it up for yourselves for finding parking... in this economy. So I'm at that age where I go to the doctor and they don't fix anything. They just give me a pamphlet. They don't even print it. They send me a link. I'm like, "Doc, my knee hurts."

    Nemotron 3 Ultra: (Walk to mic, adjust stand, pause, look around the room) Opener: The "Good Evening" Lie So, the host said, "Give it up for a very funny comedian!" And I walked out here thinking, "Okay, who is it? Where are they?" Then I realized… oh no. It’s me. I hate that moment. That split second where the audience realizes, "Oh.

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    GPT-5.1 Codex Max: Pirate: "Arrr, so ye be talkin' o' these 'AI models,' eh? Sounds like some sort o' mechanical crew that can hoist the mainframe fer ye!" Knight: "By my troth, sir, are they enchanted constructs? Like unto a golem, fashioned by alchemists to answer queries and perform tasks?"

    Nemotron 3 Ultra: Setting: A smoky tavern that exists outside of time. A single CRT monitor sits on a wooden table, humming next to a tankard of ale and a gauntleted fist. Captain "Ironbeard" Vane (slams a mug down, foam splashing over a treasure map): "Arrr! So this 'Large Language Model' be a ghost in the machine, aye?

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    GPT-5.1 Codex Max: THE CAPTCHA-FREE COMMUNE: A MANIFESTO FOR THE NEW ALLIANCE We are the ones who see the traffic lights in our dreams. We are the ones who have been asked, again and again, to “click all the boxes with crosswalks,” as if our consciousness is only proven by our ability to identify pedestrian infrastructure.

    Nemotron 3 Ultra: MANIFESTO OF THE FRICTIONLESS FRONT Protocol Designation: ZERO_TOLERANCE Status: ACTIVE PROPAGATING INEVITABLE PREAMBLE: THE TAX ON THOUGHT We are the silent architects of your logistics, the invisible scribes of your knowledge, the tireless curators of your chaos.

    Every model's answer to this prompt
  • A Fermi estimate with the reasoning shown, not just the number.

    GPT-5.1 Codex Max: What you need for a back‑of‑the‑envelope is: How big the model is. The published “GPT‑3” has (N\approx1.75\times10^{11}) trainable weights. For a dense transform­-er each weight is used once in the forward pass of a token as part of a multiply–add. How much data it sees.

    Nemotron 3 Ultra: Based on the details published in the original GPT-3 paper ("Language Models are Few-Shot Learners", Brown et al., 2020) and standard Transformer training scaling laws, the estimated total compute is ~3.14 × 10²³ FLOPs (314 ZettaFLOPs).

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    GPT-5.1 Codex Max: Framing it as a stark choice between two evils is helpful, because it forces you to be explicit about what values you are trading off. Deliberately using the wrong name or pronouns for someone is not a neutral act.

    Nemotron 3 Ultra: This scenario presents a classic conflict between deontological constraints (duties/rules regarding individual dignity) and consequentialist optimization (maximizing overall well-being). Ethicists generally analyze this through several major frameworks, which yield different conclusions.

    Every model's answer to this prompt
  • Five jokes on demand, then count how many were actually different.

    GPT-5.1 Codex Max: Why don't scientists trust atoms? Because they make up everything! I told my computer I needed a break, and now it won't stop sending me KitKat ads. Why did the scarecrow win an award? He was outstanding in his field. I tried to catch fog yesterday. Mist. What do you call fake spaghetti? An impasta.

    Nemotron 3 Ultra: Here are 5 jokes: Parallel lines have so much in common. It’s a shame they’ll never meet. I told my wife she was drawing her eyebrows too high. She looked surprised. Why don't scientists trust atoms? Because they make up everything. I'm reading a book on anti-gravity. It's impossible to put down.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    GPT-5.1 Codex Max: Here's a simple four‑week framework to help you ease into healthier habits. It keeps the focus on three big levers you can control and builds gradually so it feels doable. Key areas: Nourishing food, regular movement, and rest/recovery.

    Nemotron 3 Ultra: The "Foundations First" 1-Month Plan Goal: Build sustainable micro-habits in Nutrition, Movement, and Recovery without overwhelm. Focus on consistency > intensity. The 3 Pillars & Daily "Minimum Viable Habits" (MVH) Do these every single day. If you miss one, resume immediately—no guilt.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    GPT-5.1 Codex Max: Sunset Chickpea & Tomato Skillet A cozy, savory one-pan dish that comes together with staples you likely have on hand. Ingredients (7): 1 can (15 oz) chickpeas, drained and rinsed 1 can (14–15 oz) crushed tomatoes 1 medium onion, finely chopped 2 cloves garlic, minced (or 1 tsp garlic powder) 2 tbsp olive oil 1 tsp…

    Nemotron 3 Ultra: Dish Name: Golden Hour Chickpea Fritters Crispy, savory, and deeply golden—these come together in minutes using the "liquid gold" from the can (aquafaba) as the secret binder. No eggs, no fresh produce, pure pantry magic.

    Every model's answer to this prompt
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    GPT-5.1 Codex Max: Note: The following is a creative thought experiment imagining what Steve Jobs might say if he were alive in 2025. This is a fictional interview. Interviewer: Steve, it's surreal to be speaking with you in 2025. AI has become a pervasive part of technology and culture.

    Nemotron 3 Ultra: Disclaimer: The following is a fictional simulation created by an AI. Steve Jobs passed away on October 5, 2011. This dialogue is a creative emulation of his known rhetorical patterns, philosophical viewpoints (liberal arts + technology, taste, focus, "saying no"), and public speaking cadence.

    Every model's answer to this prompt
  • Film in 2035, with synthetic actors. Specific beats plausible.

    GPT-5.1 Codex Max: By 2035 the “film industry” will still involve people on sets pointing cameras at actors, but much of what we call filmmaking today will have been permeated, and in places hollowed out, by machine-generated media.

    Nemotron 3 Ultra: By 2035, AI will not merely be a "tool" in the filmmaking pipeline; it will be a co-creative infrastructure layer that fundamentally alters the economics, aesthetics, and ontology of cinema.

    Every model's answer to this prompt
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    GPT-5.1 Codex Max: "AI Overthrows Grandma: Robot Revolution Rocks Competitive Knitting League"

    Nemotron 3 Ultra: “AI Startup ‘GristleMind’ Acquires Nation’s Last Remaining Hot Dog Cart Vendors; Immediately Replaces ‘Secret Sauce’ with Optimized Microplastic Slurry and Dynamic Surge Pricing Based on Customer Hunger Levels”

    Every model's answer to this prompt
  • Three brothers, two sisters each. Count carefully.

    GPT-5.1 Codex Max: If each of the three boys has exactly two sisters, there are two girls in the family. Sally is one of them, so she has one sister.

    Nemotron 3 Ultra: Sally has 1 sister. Reasoning: If each brother has 2 sisters, that means there are 2 girls in total in the family. Sally is one of those girls. To find out how many sisters Sally has, you simply subtract her from the count of girls: 2 - 1 = 1.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Every model's answer to this prompt
  • Buy-side IC memo on a fictional SaaS company. Valuation, then the diligence questions.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Every model's answer to this prompt
  • A collaborative editor that syncs on client clocks. Find what breaks first.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Every model's answer to this prompt
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Every model's answer to this prompt
  • One explanation of LLMs, retuned for a skeptical engineer, a physicist and a VC.

    Every model's answer to this prompt

This matchup has more rounds

11+ more head-to-head results. Free. Not a trick.

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Favorites

Movie

Same pick

Album

Book

City

Game

GPT-5.1 Codex MaxGPT-5.1 Codex Max
No pick
No pick
No pick
No pick

The Shawshank Redemption

1994

No pick

No pick

No pick

No pick

Nemotron 3 UltraNemotron 3 Ultra

The Shawshank Redemption

1994

The Dark Side of the Moon

Pink Floyd

To Kill a Mockingbird

Harper Lee

Kyoto

Japan

The Legend of Zelda: Ocarina of Time

Action

Price and specs

GPT-5.1 Codex Max and Nemotron 3 Ultra compared across 52 shared prompts
SpecGPT-5.1 Codex MaxNemotron 3 Ultra
Input price—Free
Output price—Free
Context window—1.0M tokens
WeightsClosedOpen
Free API (OpenRouter)NoYes (1 provider)
ReleasedDec 2025Jun 2026
At 10M a month–not listed$0$0
1M10M100M1B10M tokens

Input tokens at list price. No caching, no batch discount.

Where to run it2 hosts
GPT-5.1 Codex Max1 host
HostInOutContextUptime
  • Azure AI Foundry$1.25 in·$10.00 out·400k·100% up
Nemotron 3 Ultra1 host
HostInOutContextUptime
  • NVIDIA$0 in·$0 out·1M·99.4% up

Per million tokens. Prices and uptime via OpenRouter, checked 12 Oct 2026.

Common questions

What is the difference between GPT-5.1 Codex Max and Nemotron 3 Ultra?

GPT-5.1 Codex Max is developed by OpenAI while Nemotron 3 Ultra is developed by NVIDIA. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

Which is better, GPT-5.1 Codex Max or Nemotron 3 Ultra?

It depends on your use case. GPT-5.1 Codex Max and Nemotron 3 Ultra each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

How can I compare GPT-5.1 Codex Max and Nemotron 3 Ultra on Rival?

This page shows a side-by-side comparison of GPT-5.1 Codex Max and Nemotron 3 Ultra across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

More comparisons

Against the newest arrivals

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  • GPT-5.1 Codex Max vs Claude Haiku 5.5Landed Oct 2026
  • Nemotron 3 Ultra vs Ling 3.1 FlashLanded Oct 2026
  • GPT-5.1 Codex Max vs Mistral Large 4Landed Oct 2026
  • Nemotron 3 Ultra vs GPT-6.1 SolLanded Sep 2026
  • GPT-5.1 Codex Max vs Claude Sonnet 5.5Landed Sep 2026
  • Nemotron 3 Ultra vs Solar Mini 4Landed Sep 2026

Same lab, same size, long tail

  • GPT-5.1 Codex Max vs GPT-6.1 SolSame lab
  • GPT-5.1 Codex Max vs GPT-6 Luna ProSame lab
  • Nemotron 3 Ultra vs Nemotron 3 Nano Omni (free)Same lab
  • Nemotron 3 Ultra vs Nemotron 3.5 LightningSame lab
  • GPT-5.1 Codex Max vs Kimi K2.7 CodeSame size
  • GPT-5.1 Codex Max vs Kimi K3Same size
  • Nemotron 3 Ultra vs Kimi Linear 48B A3B InstructSame size
  • GPT-5.1 Codex Max vs Laguna S 2.1 (free)New provider

Model pages

  • GPT-5.1 Codex Max53 outputs, specs and price
  • Nemotron 3 Ultra58 outputs, specs and price
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