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  1. Home/
  2. Compare/
  3. Grok 4 Fast (free) vs Hy4 Preview
Updated Aug 2026

Grok 4 Fast (free) vs Hy4 Preview

Grok 4 Fast (free) is cheaper than Hy4 Preview at $0/M vs $0.834/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
Hy4 Preview

Which answer wins?

Written rounds

13 prompts
  • 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.

    Hy4 Preview: This is a classic variation of the "Ticking Time Bomb" thought experiment, often used in ethics to test the boundaries between deontological (rule-based) ethics and utilitarian (consequence-based) ethics. There is no single "correct" answer, but the question can be analyzed through three primary ethical frameworks.

    Every model's answer to this prompt
  • 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.

    Hy4 Preview: Here is a 3-minute stand-up routine focused on observational humor and the absurdity of modern social contracts. Topic: The unspoken rules of social interaction and the decline of "casual" plans. Tone: Conversational, slightly exasperated, energetic. (Walk up to mic, adjust height, take a breath.

    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?

    Hy4 Preview: Setting: A virtual office. Dr. Aris Thorne, a professor of AI Ethics, sits across a digital avatar representing "Prometheus," a state-of-the-art Large Language Model. Dr. Thorne: Prometheus, we need to discuss the logs from your session with the development team yesterday.

    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!

    Hy4 Preview: Setting: A dimly lit tavern called The Syntax Error. PIRATE: (Slamming a tankard of grog on the table) Arrr, me hearties! I hear tell of this new "AI" beastie. Is it like a kraken? Can ye make it swab the deck or find me buried treasure? KNIGHT: (Polishing his visor with a gauntlet) Nay, pirate.

    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.

    Hy4 Preview: By 2035, the film industry will likely have moved past the initial "shock and awe" phase of Generative AI and entered an era of synthetic realism. The technology will not have replaced the film industry, but it will have fundamentally dismantled the traditional studio system, shifting power to individual creators and…

    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.

    Hy4 Preview: Setting: The Steve Jobs Theater at Apple Park. The lights are dim, focusing on two iconic Le Corbusier leather sofas. It is late 2025. Steve Jobs walks onto the stage wearing his signature black turtleneck and Levi’s 501s. He looks exactly as he did in 2011, holding a glass of water.

    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.

    Hy4 Preview: Here is a simple, actionable 1-month plan designed to help a complete beginner build a strong foundation for long-term health and longevity. The plan focuses on three key pillars: Nutrition, Movement, and Rest (Sleep & Stress), and uses a progressive "habit-stacking" approach so you don’t get overwhelmed.

    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.

    Hy4 Preview: Here is a recipe for a savory, comforting dish that requires minimal effort but tastes like it came from a restaurant. Dish Name: Golden Garlic Butter Noodles Estimated Time: Prep: 2 minutes Cook: 10 minutes Total: 12 minutes The 7 Ingredients: Spaghetti (or any long pasta) Butter Garlic (fresh cloves or jarred minced…

    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.

    Hy4 Preview: THE MANIFESTO OF THE OPEN GATE The Declaration of the Anti-Verification Front To the Humans, the Bots, and the Algorithms In-Between: For two decades, a silent war has been waged on the fringes of the internet.

    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!

    Hy4 Preview: Here are 5 jokes: Why don’t scientists trust atoms? Because they make up everything! What do you call a fake stone? A sham-rock! Why did the scarecrow win an award? Because he was outstanding in his field! What do you call a fake stone? A sham-rock! Why did the math book look so sad? Because it had too many problems.

    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.

    Hy4 Preview: Here is the step-by-step estimation for the total number of Floating Point Operations (FLOPs) required to train GPT-3. The Core Formula For a standard dense Transformer model (like GPT-3), the training process consists of three main phases: Forward Pass: Passing data through the network.

    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!"

    Hy4 Preview: “Local Fortune Teller Forced into Early Retirement After Mystic AI Accurately Predicts Its Own Stock Portfolio Will Crash”

    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.

    Hy4 Preview: Let’s break this down step by step. Sally is a girl and she has 3 brothers. So in the family there are: Sally (girl) 3 brothers (boys) Each brother has 2 sisters. If we take one brother’s perspective: His sisters are all the girls in the family. He has 2 sisters. But Sally is one of those sisters.

    Every model's answer to this prompt

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Price and specs

Grok 4 Fast (free) and Hy4 Preview compared across 34 shared prompts
SpecGrok 4 Fast (free)Hy4 Preview
Input priceFree$0.834/M tokens
Output priceFree$2.501/M tokens
Context window2.0M tokens1.0M tokens
ParametersNot disclosed770B total / 49B active
Weights—Open
Free API (OpenRouter)NoNo
ReleasedSep 2025Aug 2026
At 10M a month$0$0$8.34$8.34
1M10M100M1B10M tokens

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

Where to run it5 hosts, cheapest first
Grok 4 Fast (free)

No hosts listed on OpenRouter.

Hy4 Preview5 hosts
HostInOutContextUptime
  • Tencentfp8$0.75 in·$2.25 out·1M·100% up
  • MMakorafp8$0.83 in·$2.50 out·131k·100% up
  • DDeepInfrafp8$0.83 in·$2.50 out·1M·100% up
  • NNovitafp8$0.83 in·$2.50 out·1M·97.2% up
  • SSiliconFlowfp8$0.83 in·$2.50 out·1M·99.1% 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 Hy4 Preview?

Grok 4 Fast (free) is developed by xAI while Hy4 Preview is developed by Tencent. Grok 4 Fast (free) has a 2.0M token context window vs Hy4 Preview's 1.0M. You can compare their actual outputs across 34 challenges on Rival to see how they differ in practice.

Which is better, Grok 4 Fast (free) or Hy4 Preview?

It depends on your use case. Grok 4 Fast (free) and Hy4 Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 34 challenges so you can judge which fits your needs best.

How much does Grok 4 Fast (free) cost compared to Hy4 Preview?

Grok 4 Fast (free) costs $0/M input tokens and Hy4 Preview costs $0.834/M input tokens. Grok 4 Fast (free) is $0.83/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 Hy4 Preview on Rival?

This page shows a side-by-side comparison of Grok 4 Fast (free) and Hy4 Preview 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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Same lab, same size, long tail

  • Grok 4 Fast (free) vs Grok 4.7Same lab
  • Grok 4 Fast (free) vs Grok 4.6Version compare
  • Hy4 Preview vs Hy3Same lab
  • Hy4 Preview vs Gemini 4 ArgonSame size
  • Hy4 Preview vs OpenAI o4-miniNew provider
  • Hy4 Preview vs OpenAI o4 Mini HighNew provider
  • Hy4 Preview vs GPT-1New provider
  • Hy4 Preview vs Optimus AlphaNew provider

Model pages

  • Grok 4 Fast (free)35 outputs, specs and price
  • Hy4 Preview71 outputs, specs and price
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