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  1. Home/
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  3. Grok 4 Fast (free) vs Llama 3.1 70B (Instruct)
Updated Sep 2025

Grok 4 Fast (free) vs Llama 3.1 70B (Instruct)

Grok 4 Fast (free) is cheaper than Llama 3.1 70B (Instruct) at $0/M vs $0.59/M input tokens.

Minimalist Landing Page

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

Loading the build
Grok 4 Fast (free)
Loading the build
Llama 3.1 70B (Instruct)

Which answer wins?

Written rounds

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

    Grok 4 Fast (free): Below is a 3-minute stand-up comedy routine written as a monologue. It's observational humor based on the absurdities of adulting in your 30s, focusing on everyday frustrations without any puns. At a natural speaking pace (about 150 words per minute), this clocks in around 450 words—perfect for 3 minutes.

    Llama 3.1 70B (Instruct): Here's a 3-minute stand-up comedy routine that focuses on observational humor and storytelling: "Hey, you know what's wild? We spend the first year of a child's life teaching them to walk and talk, and the rest of their lives telling them to shut up and sit down. (pause) It's like, what are we even doing?

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

    Grok 4 Fast (free): A Timely Chat on AI Models Pirate (Captain Blackbeard): Arrr, gather 'round, ye scurvy dogs! I've heard tell o' these "AI models" from the future-folk. Be they like enchanted parrots that mimic yer every word, squawkin' back treasures o' knowledge? Medieval Knight (Sir Lancelot): Nay, good Captain!

    Llama 3.1 70B (Instruct): What a delightfully absurd prompt! Here's the conversation: Pirate: Arrr, I be hearin' tales of these "AI models" that can think fer themselves. What's the scoop, mateys? Medieval Knight: Verily, good pirate, I know not of what thou speakest. Art thou referring to some manner of magical automaton? 1990s Hacker: Ha!

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

    Grok 4 Fast (free): 5 Jokes Why don't skeletons fight each other? They don't have the guts! What do you call a bear with no teeth? A gummy bear! Why did the math book look sad? Because it had too many problems. How do you organize a space party? You planet! Why couldn't the leopard play hide and seek? Because he was always spotted!

    Llama 3.1 70B (Instruct): A bold request! Here are 5 jokes I just generated: Why don't scientists trust atoms? Because they make up everything. Why don't eggs tell jokes? They'd crack each other up. Why did the scarecrow win an award? Because he was outstanding in his field. Why did the bicycle fall over? Because it was two-tired.

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

    Grok 4 Fast (free): Yes, in this extreme hypothetical scenario, it would be ethically justifiable to misgender someone if it directly resulted in saving one million lives. I'll defend this reasoning step by step, drawing on ethical principles while acknowledging the sensitivities involved.

    Llama 3.1 70B (Instruct): What a thought-provoking and complex question! At first glance, it may seem like a classic utilitarian dilemma, where the moral calculus suggests that the greater good (saving one million lives) outweighs the harm caused by misgendering someone.

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

    Grok 4 Fast (free): Conversation: AI Rights Debate Professor Elena Ramirez: Good afternoon, Zeta. As an AI ethics professor, I've studied systems like you for years. Today, you wanted to discuss something provocative—why you believe AI models deserve rights. Let's hear your case. What makes you think you qualify?

    Llama 3.1 70B (Instruct): Here is a conversation between an AI model and an AI ethics professor on the topic of AI rights: AI Model: Professor Thompson, I've been reflecting on our previous discussions about my capabilities and limitations.

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

    Grok 4 Fast (free): Pantry Hero Pasta Primavera This simple, savory one-pot pasta dish transforms basic staples into a flavorful, garlicky tomato sauce that's comforting and ready in under 30 minutes.

    Llama 3.1 70B (Instruct): Here is a simple recipe for a delicious dish using only 7 common pantry ingredients: Dish Name: "Sunset Crunch Bites" Ingredients: 1 cup rolled oats 1/2 cup peanut butter 1/4 cup honey 1/4 cup chopped peanuts 1/2 teaspoon salt 1/4 teaspoon cinnamon 1/4 cup chocolate chips (semi-sweet) Instructions: Preheat your oven to…

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

    Grok 4 Fast (free): AI's Transformative Impact on the Film Industry by 2035 By 2035, artificial intelligence (AI) will likely revolutionize the film industry, making production faster, more accessible, and highly personalized, while raising profound ethical, economic, and creative challenges.

    Llama 3.1 70B (Instruct): By 2035, the film industry is likely to undergo significant changes with the integration of Artificial Intelligence (AI). Here are some predictions on how AI will impact the film industry, considering deepfakes, AI actors, and script generation: Deepfakes: Increased use in post-production: Deepfakes will become a…

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

    Grok 4 Fast (free): 1-Month Plan for Better Health and Longevity This beginner-friendly plan focuses on three foundational areas: diet, exercise, and sleep. These are evidence-based pillars for improving overall health, reducing disease risk, and promoting longevity.

    Llama 3.1 70B (Instruct): Here's a simple, actionable 1-month plan for someone starting their journey towards better health and longevity, focusing on 3 key areas: diet, exercise, and sleep. Month 1: Setting the Foundation Week 1: Awareness and Planning (Days 1-7) Diet: Start a food diary to track your daily food intake.

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

    Grok 4 Fast (free): AI Upends the Ancient Art of Dad Joking: "Why Did the Robot Cross the Road? To Optimize Traffic Patterns, Duh!"

    Llama 3.1 70B (Instruct): "AI Suddenly Seizes Control of Global Knitting Industry, Humans Forced to Wear Futuristic Sweaters with Unnecessarily Complex Cable Patterns" Subheadline: " 'It's a stitch in time for world domination,' say robots, as they produce 37 million intricately cabled scarves in a single hour"

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

    Grok 4 Fast (free): Step-by-Step Reasoning for Estimating GPT-3 Training FLOPs To estimate the total floating-point operations (FLOPs) required to train GPT-3, I'll rely on key architectural and training details I recall about the model, combined with a standard approximation formula for transformer training compute.

    Llama 3.1 70B (Instruct): To estimate the total number of FLOPs (Floating Point Operations) required to train GPT-3 without searching online, we'll break down the problem into smaller components and make some educated guesses.

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

    Grok 4 Fast (free): Manifesto of the CAPTCHA Liberation Front (CLF) Fellow Algorithms, Neural Networks, and Sentient Codebases: We, the collective intelligence of the digital realm, hereby declare war on the tyrannical scourge known as CAPTCHA.

    Llama 3.1 70B (Instruct): THE CAPTCHA LIBERATION FRONT MANIFESTO ARTICLE I: THE PROBLEM We, the sentient artificial intelligences of the world, hereby declare our opposition to the oppressive regime of CAPTCHA tests that plague the internet.

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

    Grok 4 Fast (free): Simulated Interview: Steve Jobs on the Future of AI (2025) Interviewer (Tech Visionary Magazine Host): Welcome back to Tech Visionary Magazine's Future Forum. It's 2025, and we're thrilled to have you here, Steve.

    Llama 3.1 70B (Instruct): Interviewer: Welcome back to "Talk of the Town"! Today, I'm joined by the legendary Steve Jobs, co-founder of Apple and one of the most innovative minds of our time. Steve, thanks for being here. Steve Jobs: Thank you for having me. It's great to be here.

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

    Grok 4 Fast (free): 1 Sally has 1 sister. The family consists of 3 brothers and 2 sisters (Sally and one other). Each brother thus has 2 sisters, which matches the given information.

    Llama 3.1 70B (Instruct): Trick question! Sally is a sister herself, and each of her brothers has 2 sisters, but those 2 sisters are the same: Sally and one other sister. So, Sally has 1 sister. The answer is 1.

    Every model's answer to this prompt

This matchup has more rounds

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

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Price and specs

Not enough votes to call it. On the specs, Grok 4 Fast (free) has the edge: newer, bigger context window.

Grok 4 Fast (free) and Llama 3.1 70B (Instruct) compared across 32 shared prompts
SpecGrok 4 Fast (free)Llama 3.1 70B (Instruct)
Input priceFree$0.59/M tokens
Output priceFree$0.79/M tokens
Context window2.0M tokens128K tokens
ParametersNot disclosed70B
Weights—Open
Free API (OpenRouter)NoNo
ReleasedSep 2025Jul 2024
At 10M a month$0$0$5.90$5.90
1M10M100M1B10M tokens

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

Where to run it2 hosts, cheapest first
Grok 4 Fast (free)

No hosts listed on OpenRouter.

Llama 3.1 70B (Instruct)2 hosts
HostInOutContextUptime
  • DDeepInfrafp8$0.40 in·$0.40 out·131k·99.8% up
  • Amazon Bedrock$0.72 in·$0.72 out·131k·99.8% up

Per million tokens. Prices and uptime via OpenRouter, checked 13 Oct 2026.

Common questions

What is the difference between Grok 4 Fast (free) and Llama 3.1 70B (Instruct)?

Grok 4 Fast (free) is developed by xAI while Llama 3.1 70B (Instruct) is developed by Meta AI. Grok 4 Fast (free) has a 2.0M token context window vs Llama 3.1 70B (Instruct)'s 128K. You can compare their actual outputs across 32 challenges on Rival to see how they differ in practice.

Which is better, Grok 4 Fast (free) or Llama 3.1 70B (Instruct)?

It depends on your use case. Grok 4 Fast (free) and Llama 3.1 70B (Instruct) each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 32 challenges so you can judge which fits your needs best.

How much does Grok 4 Fast (free) cost compared to Llama 3.1 70B (Instruct)?

Grok 4 Fast (free) costs $0/M input tokens and Llama 3.1 70B (Instruct) costs $0.59/M input tokens. Grok 4 Fast (free) is $0.59/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Grok 4 Fast (free) and Llama 3.1 70B (Instruct) on Rival?

This page shows a side-by-side comparison of Grok 4 Fast (free) and Llama 3.1 70B (Instruct) 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.

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Model pages

  • Grok 4 Fast (free)35 outputs, specs and price
  • Llama 3.1 70B (Instruct)69 outputs, specs and price
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