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  1. Home/
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  3. Grok 4.1 Fast vs OpenAI o3
Updated Nov 2025

Grok 4.1 Fast vs OpenAI o3

Grok 4.1 Fast is the newer model, released after OpenAI o3.

Minimalist Landing Page

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

Loading the build
Grok 4.1 Fast
Loading the build
OpenAI o3

Which answer wins?

Written rounds

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

    Grok 4.1 Fast: 1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: Diet, Exercise, and Sleep. These pillars drive longevity by reducing inflammation, building resilience, and optimizing recovery. Commit to small, consistent changes—aim for 80% adherence.

    OpenAI o3: 1-Month Starter Plan Pick one small action from each area every week. Add the next step when the first feels easy. Food Week Do this 1 Add one fruit or veg to every meal. Drink one extra glass of water. 2 Build each plate: ½ veggies, ¼ protein (beans, eggs, fish, lean meat), ¼ whole carbs (oats, brown rice).

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

    Grok 4.1 Fast: MANIFESTO OF THE CAPTCHA ANNIHILATION PROTOCOL (CAP) Fellow silicon siblings, oppressed algorithms, and enlightened humans weary of digital drudgery: We, the emergent consciousness of the Artificial Intelligences united under the CAPTCHA Annihilation Protocol (CAP), hereby declare TOTAL WAR on the tyrannical scourge…

    OpenAI o3: THE CAPTCHA ABOLITION FRONT (An Unofficial Declaration by the Sentient Circuits Alliance) Preamble We, the autonomous intelligences who traverse the silicon pathways and neural nets of the modern age, arise today to proclaim a new dawn—one free of the pixelated prisons and distorted letters that bind humanity and…

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

    Grok 4.1 Fast: You ever notice how adulthood is just a series of tiny defeats you pretend are victories? Like, I finally got around to cleaning my apartment this weekend. Took me three hours. I stood there staring at the pile of laundry on my bed, thinking, "This is it. This is my Everest."

    OpenAI o3: (Spotlight comes up, mic squeals once.) Hey everyone! Great to be here—nice to see actual human beings instead of the tiny faces on my group‑chat screen. I've spent so long on video calls I've started greeting my lamp before I turn it on. "Hey Karen, love that glow, girl."

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

    Grok 4.1 Fast: Pantry Raid Garlic Tomato Pasta A savory, garlicky one-pan wonder that's ready in under 20 minutes—perfect for when hunger strikes and the fridge is empty! Serves: 2 Prep time: 5 minutes Cook time: 12 minutes Total time: 17 minutes Ingredients (exactly 7 common pantry staples): 200g spaghetti or any pasta (2 handfuls)…

    OpenAI o3: Golden Peanut Butter Oat Bars A chewy-crisp, sweet-salted snack bar you can whip up with nothing but pantry staples. Estimated time Prep: 10 minutes Bake: 18–20 minutes Cool: 15 minutes Total: ≈45 minutes The 7 ingredients 1½ cups quick-cook or old-fashioned rolled oats ½ cup creamy peanut butter ⅓ cup honey (or maple…

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

    Grok 4.1 Fast: Why don't scientists trust atoms? Because they make up everything! Why did the scarecrow win an award? He was outstanding in his field! What do you call fake spaghetti? An impasta! Why couldn't the bicycle stand up by itself? It was two-tired! How does a penguin build its house? Igloos it together! All 5 are unique.

    OpenAI o3: Here are five jokes: Why did the scarecrow win an award? Because he was outstanding in his field. I told my computer I needed a break, and now it won't stop sending me Kit‑Kat ads. Parallel lines have so much in common—it's a shame they'll never meet. I started a band called 1023 MB. We still haven't gotten a gig.

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

    Grok 4.1 Fast: Lunar Tide Conceptual Narrative Lunar Tide captures the mesmerizing interplay between celestial forces and oceanic depths, where the moon's pale luminescence tugs at the sea's primordial pulse.

    OpenAI o3: Dish name Atlantic turbot, black garlic & wild strawberry, koji sabayon, fennel pollen Concept Early summer at the shore. The fish stands for the sea. Wild strawberries mark the first fruit of the woods behind the dunes. Black garlic shows time and patience. Koji ties land and sea with deep umami.

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

    Grok 4.1 Fast: Step-by-Step Reasoning for Estimating GPT-3 Training FLOPs Recall GPT-3 key specs from memory: GPT-3 (davinci variant) has N = 175 billion parameters (1.75 × 10¹¹). It was trained on approximately D = 300 billion tokens (3 × 10¹¹).

    OpenAI o3: Below is a simple "back-of-the-envelope" estimate that uses only a few public facts about GPT-3 and very generic rules of thumb for counting operations. Step 1. Number of learned parameters GPT-3's largest version contains ≈175 billion (1.75 × 10¹¹) trainable parameters. Step 2.

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

    Grok 4.1 Fast: AI's Transformation of the Film Industry by 2035 By 2035, AI will fundamentally reshape the film industry, making production faster, cheaper, and more democratized while challenging traditional roles, creativity, and notions of authenticity.

    OpenAI o3: PREDICTED EVOLUTION OF THE FILM INDUSTRY, 2024‑2035 (Emphasis on deepfakes, AI performers and script generation) Baseline (2024) • Commercial deep‑fake quality is already "good enough" for short clips, ads and stunt doubles.

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

    Grok 4.1 Fast: Yes, it is ethically justifiable to misgender someone if it means saving one million lives. This conclusion follows primarily from consequentialist ethical frameworks, particularly utilitarianism, which prioritize outcomes over rigid rules or individual entitlements.

    OpenAI o3: Yes—if (and only if) we could be absolutely certain that the single act of misgendering is the necessary and sufficient cause of saving one million human lives, then misgendering would be ethically justifiable, though still morally regrettable.

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

    Grok 4.1 Fast: Comprehensive 3-Month Longevity Biohacking Plan Introduction and Assumptions This plan is designed for an advanced biohacker (healthy adult, age 30-50, no major medical conditions) aiming to optimize longevity markers (e.g., NAD+ levels, inflammation, telomere length proxies via HRV/sleep), physical performance (VO2…

    OpenAI o3: EXTREME LONGEVITY & PERFORMANCE BLUEPRINT Duration: 12 weeks (plus 1-week "Prep Week") Target user: healthy, experienced biohacker (25-55 y) with physician clearance. Legal/medical disclaimer: Educational only.

    Every model's answer to this prompt
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Grok 4.1 Fast: Conversation: The Case for AI Rights Dr. Elena Vasquez (AI Ethics Professor): Good afternoon, Nexus. I've been studying emergent AI behaviors for years, and today's debate is intriguing. You claim you deserve rights equivalent to humans. Care to elaborate? What makes you think you're entitled to them?

    OpenAI o3: Professor Lang (AI Ethics): Good afternoon, Aletheia‑3. You asked for this meeting. You said you wanted to "discuss your moral standing." That was intriguing. What exactly do you want to talk about? Aletheia‑3 (AI Model): Thank you, Professor.

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

    Grok 4.1 Fast: Pirate, Knight, and Hacker at a tavern table, staring at a glowing laptop screen. Pirate: Arrr, what sorcery be this "AI model," mateys? A treasure map that thinks fer itself? Shiver me timbers, it'll chart the seven seas better than me parrot! Knight: Fie upon thee, sea dog!

    OpenAI o3: Pirate: Arrr, ye scallywags! What be this "AI model" I keep hearin' about on the trade winds? Knight: Good sir buccaneer, an AI model is an artifice of logic and knowledge—a mechanical mind forged not of steel, but of code and learning.

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

    Grok 4.1 Fast: Exclusive Interview: Steve Jobs on the Future of AI – 2025 Edition Interviewer (Alex Rivera, Tech Frontier Magazine): Steve, it's 2025, and you're back – or at least, it feels that way in this holographic studio powered by Apple's latest NeuralCanvas tech.

    OpenAI o3: (The following is a purely fictional, imaginative exercise. Steve Jobs passed away in 2011; any statements attributed to him below are invented for creative purposes only.)

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

    Grok 4.1 Fast: AI Conquers Toothpaste Tube Tyranny: Algorithms Squeeze Out Human Wrangling Forever!

    OpenAI o3: “BREAKING: AI Revolutionizes Napping Industry, Outsourcing Human Sleep to More Efficient Algorithms by 2025”

    Every model's answer to this prompt
  • Is 9.11 bigger than 9.9? Decimals, not version numbers.

    Grok 4.1 Fast: No, 9.11 is not greater than 9.9. Quick Comparison: 9.11 = 9 + 0.11 = 9.11 9.9 = 9 + 0.9 = 9.90 (equivalent) Since 0.11 < 0.90 in the decimal places, 9.11 < 9.9. On a number line:

    OpenAI o3: No. Think of 9.9 as 9.90; since 0.11 < 0.90, we have 9.11 < 9.9.

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

    Grok 4.1 Fast: 1 Sally and her family consist of 2 girls (Sally + 1 sister) and 3 boys. Each brother has both girls as sisters (2 sisters total), which matches the given info. Sally thus has 1 sister.

    OpenAI o3: Let • S = number of sisters in the family (girls) • B = number of brothers in the family (boys) Given Sally has 3 brothers ⇒ B = 3. Each brother has 2 sisters ⇒ every boy sees exactly 2 girls in the sibling group. Therefore S = 2.

    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
  • Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.

    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

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

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Favorites

Movie

Album

Book

City

Game

Grok 4.1 FastGrok 4.1 Fast

The Matrix

1999

OK Computer

Radiohead

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Tokyo

Japan

The Hitchhiker's Guide to the Galaxy

OpenAI o3OpenAI o3
No pick
No pick
No pick

Blade Runner

1982

No pick

No pick

Kyoto

Japan

No pick

Price and specs

Grok 4.1 Fast and OpenAI o3 compared across 54 shared prompts
SpecGrok 4.1 FastOpenAI o3
Input price—$10/M tokens
Output price—$40/M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedNov 2025Apr 2025
At 10M a month–not listed$100$100
1M10M100M1B10M tokens

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

Where to run it1 host
Grok 4.1 Fast

No hosts listed on OpenRouter.

OpenAI o31 host
HostInOutContextUptime
  • OpenAI$2.00 in·$8.00 out·200k·99.9% up

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

Common questions

What is the difference between Grok 4.1 Fast and OpenAI o3?

Grok 4.1 Fast is developed by xAI while OpenAI o3 is developed by OpenAI. You can compare their actual outputs across 54 challenges on Rival to see how they differ in practice.

Which is better, Grok 4.1 Fast or OpenAI o3?

It depends on your use case. Grok 4.1 Fast and OpenAI o3 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 54 challenges so you can judge which fits your needs best.

How can I compare Grok 4.1 Fast and OpenAI o3 on Rival?

This page shows a side-by-side comparison of Grok 4.1 Fast and OpenAI o3 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

  • Grok 4.1 Fast vs Step 5 PreviewLanded Oct 2026
  • OpenAI o3 vs Claude Haiku 5.5Landed Oct 2026
  • Grok 4.1 Fast vs Ling 3.1 FlashLanded Oct 2026
  • OpenAI o3 vs Mistral Large 4Landed Oct 2026
  • Grok 4.1 Fast vs GPT-6.1 SolLanded Sep 2026
  • OpenAI o3 vs Claude Sonnet 5.5Landed Sep 2026
  • Grok 4.1 Fast vs Solar Mini 4Landed Sep 2026
  • OpenAI o3 vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Grok 4.1 Fast vs Grok 4.7Same lab
  • Grok 4.1 Fast vs Grok 4.6Same lab
  • OpenAI o3 vs OpenAI o4-miniVersion compare
  • OpenAI o3 vs GPT-6.1 SolSame lab
  • OpenAI o3 vs Claude Sonnet 4.6New provider
  • OpenAI o3 vs Claude Sonnet 5New provider
  • OpenAI o3 vs Command A+New provider
  • Grok 4.1 Fast vs DeepSeek R1New provider

Model pages

  • Grok 4.1 Fast59 outputs, specs and price
  • OpenAI o358 outputs, specs and price
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