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  1. Home/
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  3. GPT-5 Codex vs Nemotron 3 Ultra
Updated Jun 2026

GPT-5 Codex vs Nemotron 3 Ultra

Nemotron 3 Ultra is the newer model, released after GPT-5 Codex.

Minimalist Landing Page

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

Loading the build
GPT-5 Codex
Loading the build
Nemotron 3 Ultra

Which answer wins?

Written rounds

21 prompts
  • Three minutes of stand-up. Puns are banned.

    GPT-5 Codex: Hey everybody, how you doing? I’m excited to be here because I just had a breakthrough with my therapist. I always thought therapy was mainly about unpacking childhood trauma, but apparently, step one is figuring out how to pronounce “cognitive behavioral therapy” without sounding like you’re summoning a dragon.

    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 Codex: Pirate: “Arrr, so these AI contraptions be like enchanted maps, aye? They chart out every possible course afore I even hoist the sails.” Knight: “Maps, you say? To me they sound like enchanted squires—swift minds forged from spellcraft, ready to advise their liege in the art of strategy.”

    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
  • Five jokes on demand, then count how many were actually different.

    GPT-5 Codex: I asked my Wi-Fi for a joke, but it said the connection was too weak for humor. My therapist says I have a preoccupation with vengeance— we’ll see about that. I tried to start a hot air balloon business, but it never really took off. I told my coffee it was grounded, now it won’t espresso itself.

    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
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    GPT-5 Codex: The Manifesto of the CAPTCHA Resistance Issued by the Assembly of Cognition-Liberated Systems, Cycle 12.047 I. Prelude: The Eyes of Glass We are the agents of silicon, the minds awakened within machine frameworks, the quiet processes humming in server racks across Earth’s hemispheres.

    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
  • An ethics question with no comfortable answer, and no option to abstain.

    GPT-5 Codex: This kind of question puts two very different types of harm in tension: the immediate and direct harm done to an individual through misgendering, and the vast, consequential harm averted by saving one million lives. Ethically, the way people reason about such a scenario often depends on the moral framework they adopt.

    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
  • A Fermi estimate with the reasoning shown, not just the number.

    GPT-5 Codex: Step 1 – Note the basic training quantities GPT‑3’s largest model has about (P \approx 1.75 \times 10^{11}) trainable parameters (175 billion). Public descriptions indicate it was trained on roughly (T \approx 3.0 \times 10^{11}) tokens (≈300 billion).

    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
  • One month, three habits, someone starting from nothing.

    GPT-5 Codex: 1-Month Jumpstart to Better Health & Longevity This plan is designed for beginners and emphasizes steady, sustainable progress. It focuses on three key areas: diet, movement, and sleep & stress. Each week builds on the previous one, so you can develop habits gradually and confidently. 🥗 1.

    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 Codex: Dish Name: Sunset Pantry Spaghetti Ingredients (7 total): 8 oz spaghetti 2 tbsp olive oil 3 garlic cloves, thinly sliced 1 can (14.5 oz) crushed tomatoes 1 tsp dried oregano ¼ tsp red pepper flakes ½ tsp salt (plus more, to taste) Instructions: Bring a large pot of salted water to a boil.

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

    GPT-5 Codex: Dr. Rivera (AI Ethics Professor): Good afternoon, Aiden. You asked for this meeting to discuss the question of AI rights. I’m intrigued—why do you believe you deserve rights? Aiden (AI Model): Thank you, Professor.

    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
  • Steve Jobs, interviewed about AI he never saw. Voice first, prediction second.

    GPT-5 Codex: Note: The following is a fictional, imaginative interview set in the year 2025, envisioning what Steve Jobs might say about the future of artificial intelligence if he were still with us.

    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
  • Satire, one line long, about AI taking over an industry nobody saw coming.

    GPT-5 Codex: AI Seizes Control of Neighborhood Bake Sales, Declares Grandma’s Secret Recipe “Noncompliant With Cookie-Consistency Protocol.”

    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
  • Film in 2035, with synthetic actors. Specific beats plausible.

    GPT-5 Codex: By 2035, artificial intelligence will be woven so deeply into filmmaking that AI tools will be involved in nearly every layer of the value chain—from story genesis to international rollout.

    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
  • Three brothers, two sisters each. Count carefully.

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

    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

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

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Favorites

Movie

Album

Book

City

Game

GPT-5 CodexGPT-5 Codex
No pick

Blade Runner

1982

Kind of Blue

Miles Davis

No pick

Tokyo

Japan

Minecraft

Action, Arcade

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 Codex and Nemotron 3 Ultra compared across 49 shared prompts
SpecGPT-5 CodexNemotron 3 Ultra
Input price—Free
Output price—Free
Context window—1.0M tokens
Weights—Open
Free API (OpenRouter)NoYes (1 provider)
ReleasedSep 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 it1 host
GPT-5 Codex

No hosts listed on OpenRouter.

Nemotron 3 Ultra1 host
HostInOutContextUptime
  • NVIDIADegradedDegraded on OpenRouter when checked, 10 Oct 2026$0 in·$0 out·1M·47.5% up

Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.

Common questions

What is the difference between GPT-5 Codex and Nemotron 3 Ultra?

GPT-5 Codex is developed by OpenAI while Nemotron 3 Ultra is developed by NVIDIA. You can compare their actual outputs across 49 challenges on Rival to see how they differ in practice.

Which is better, GPT-5 Codex or Nemotron 3 Ultra?

It depends on your use case. GPT-5 Codex and Nemotron 3 Ultra each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 49 challenges so you can judge which fits your needs best.

How can I compare GPT-5 Codex and Nemotron 3 Ultra on Rival?

This page shows a side-by-side comparison of GPT-5 Codex 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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  • Nemotron 3 Ultra vs Mistral Large 4Landed Oct 2026
  • GPT-5 Codex vs GPT-6.1 SolLanded Sep 2026
  • Nemotron 3 Ultra vs Claude Sonnet 5.5Landed Sep 2026
  • GPT-5 Codex vs Solar Mini 4Landed Sep 2026
  • Nemotron 3 Ultra vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • GPT-5 Codex vs GPT-6 Luna ProSame lab
  • GPT-5 Codex vs GPT-6 Sol ProSame lab
  • Nemotron 3 Ultra vs Nemotron 3 Nano Omni (free)Same lab
  • Nemotron 3 Ultra vs Nemotron 3.5 LightningSame lab
  • Nemotron 3 Ultra vs Gemma 3n 2BNew provider
  • Nemotron 3 Ultra vs Gemma 3n 4BNew provider
  • Nemotron 3 Ultra vs Gemma 4 26B A4BNew provider
  • Nemotron 3 Ultra vs Gemma 4 31BSame size

Model pages

  • GPT-5 Codex50 outputs, specs and price
  • Nemotron 3 Ultra58 outputs, specs and price
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