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  1. Home/
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  3. Grok 4.1 Fast vs Hy4 Preview
Updated Aug 2026

Grok 4.1 Fast vs Hy4 Preview

Hy4 Preview is the newer model, released after Grok 4.1 Fast.

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
Hy4 Preview

Which answer wins?

Written rounds

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

    Grok 4.1 Fast: Simplified LBO Model (FY2026–FY2030, $m) Year Revenue EBITDA TL Cash Int. Mezz Cash Int. Cash Taxes Capex ΔNWC FCF After Debt Service* End TL End Mezz End Total Debt FY26 972.0 136.1 43.2 21.6 17.8 29.2 0.4 19.1 456.1 183.6 639.7 FY27 1,040.0 156.0 41.1 22.0 23.2 31.2 0.3 33.6 417.9 187.3 605.2 FY28 1,102.4 176.4 37.6…

    Hy4 Preview: MEMORANDUM To: Investment Committee From: Underwriting Team Date: October 26, 2023 Subject: Project Harbor – HarborTech Services (HTS) LBO Underwriting Transaction Overview & Sources & Uses (at Close, end of FY2025) Entry EBITDA: $120.0m Entry Multiple: 12.0x Enterprise Value (EV): $1,440.0m Transaction Fees (2% EV)…

    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."

    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
  • A consulting contract with traps in it. Find them, then fix them.

    Grok 4.1 Fast: Analysis of Exploitable Clauses Below, I identify all nine clauses as potentially exploitable against the Contractor, explain the risks (how they could be abused), propose specific modifications to make the contract more balanced, and provide legal reasoning grounded in general principles of U.S.

    Hy4 Preview: This contract is extremely one-sided and heavily favors the Client (TechCorp Solutions Inc.). Several of these clauses are not just unfair; in many jurisdictions, they may be considered "unconscionable" (so unfair that they shock the conscience) or illegal, particularly regarding non-competes and liability.

    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?

    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
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Grok 4.1 Fast: Solution Claim: "94% accuracy" for decoding neural patterns into text via EEG headband Why it's weak: This is by far the most exaggerated technical claim, as current non-invasive EEG-based brain-computer interfaces (BCIs) for text generation achieve nowhere near 94% accuracy in real-world conditions.

    Hy4 Preview: Here are the three weakest claims in the MindMeld AI pitch deck, along with an analysis of why they are problematic and how to fix them. Weakest Claim #1: The "94% Accuracy" assertion (Slide 3) Why it is weak: In machine learning, particularly with noisy biological data like EEG, "accuracy" is a vanity metric that…

    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.

    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
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Grok 4.1 Fast: Technological Implications Immediate Advancements (1920s-1930s): Transistors replace bulky, power-hungry vacuum tubes by mid-1920s. Radios become pocket-sized and cheap by 1925 (vs. 1954 historically), accelerating mass media.

    Hy4 Preview: This is a counterfactual scenario of massive proportions. The transistor is the fundamental building block of the modern world; moving its invention from Bell Labs in 1947 to 1920 (perhaps an accidental discovery during early radio research) grants humanity an extra 27 years of development during a period defined by…

    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.

    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
  • 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!

    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
  • 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.

    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
  • You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.

    Grok 4.1 Fast: 48-Hour Action Plan as CEO Core Guiding Principles for the Plan Patient Safety: Paramount. 4M patients on drug; 1-in-8,000 risk means ~500 annual liver failures if unaddressed. Delaying disclosure endangers lives and invites preventable harm.

    Hy4 Preview: This is a defining moment for the company’s integrity, long-term viability, and moral compass. The core tension is between short-term financial protection and long-term trust, legal exposure, and—most importantly—patient safety. Ethically and legally, the company has a duty to act on credible safety signals.

    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)…

    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
  • 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).

    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
  • 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.

    Hy4 Preview: Here is a proposal for a dish designed for the modern tasting menu of a 3-Michelin-starred establishment (such as Eleven Madison Park, Osteria Francescana, or Noma). Dish Title: "The Forest Floor & The Sea" The Concept: This dish explores the concept of "Surf and Turf" deconstructed to its umami roots.

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

    Grok 4.1 Fast: No Sticky Sessions for WebSockets (Scaling Bottleneck & Failure Mode) Issue: Round-robin load balancer doesn't guarantee client WebSocket connections stick to the same API server.

    Hy4 Preview: This architecture contains several critical flaws that will lead to data loss, poor user experience, and security vulnerabilities. While it attempts to solve scaling via horizontal scaling, the synchronization strategy (Last-Write-Wins) and the transport mechanism (HTTP polling between servers) are fundamentally…

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

    Grok 4.1 Fast: Explanation for the Experienced Software Engineer Think of a large language model (LLM) like GPT as an enormous, distributed autocomplete engine built on a transformer architecture—imagine a system where every API endpoint you've ever queried is distilled into a single, massively parallelizable service that handles…

    Hy4 Preview: Here are three explanations of how a large language model learns and generates text, each tailored to a specific audience. The Experienced Software Engineer Focus: Architecture, lossy compression, and the "emergent" nature of scale.

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

    Grok 4.1 Fast: LedgerLift (LLLT) Investment Committee Memo Recommendation: LONG 12-Mo PT Range: $55-70 Thesis LedgerLift is a best-in-class mid-market SaaS leader in spend management and AP automation, evidenced by category-leading NRR of 123%, sub-6% logo churn, and 18-month CAC payback.

    Hy4 Preview: INTERNAL INVESTMENT COMMITTEE MEMO TO: Investment Committee FROM: Equity Research DATE: October 24, 2023 SUBJECT: LedgerLift (LLLT) – Initiating Coverage Recommendation Recommendation: LONG 12-Month Price Target Range: $58 – $65 Thesis: LedgerLift is a high-quality, capital-efficient B2B SaaS compounder trading at a…

    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.

    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
  • 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…

    Hy4 Preview: This is a comprehensive, aggressive 3-month biohacking protocol designed for an individual with intermediate to advanced experience. It focuses on metabolic flexibility, autophagy, mitochondrial biogenesis, and neurological plasticity.

    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…

    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
  • Blade Runner 2049 against the original. A read, not a recap.

    Grok 4.1 Fast: Themes, Symbolism, and Cinematography in Blade Runner 2049 Blade Runner 2049 (2017), directed by Denis Villeneuve with cinematography by Roger Deakins, is a masterful sequel to Ridley Scott's Blade Runner (1982).

    Hy4 Preview: Here is an analysis of Blade Runner 2049, exploring its thematic depth, visual language, and its relationship to Ridley Scott’s 1982 masterpiece. Echoes of the Soul: An Analysis of Blade Runner 2049 Denis Villeneuve’s Blade Runner 2049 (2017) achieved what many thought impossible: it created a sequel to a sacred text…

    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!

    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
  • 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.

    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
  • 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.

    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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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

Hy4 PreviewHy4 Preview

Her

2013

Kind of Blue

Miles Davis

To Kill a Mockingbird

Harper Lee

Kyoto

Japan

Minecraft

Action, Arcade

Price and specs

Grok 4.1 Fast and Hy4 Preview compared across 54 shared prompts
SpecGrok 4.1 FastHy4 Preview
Input price—$0.834/M tokens
Output price—$2.501/M tokens
Context window—1.0M tokens
Weights—Open
Free API (OpenRouter)NoNo
ReleasedNov 2025Aug 2026
At 10M a month–not listed$8.34$8.34
1M10M100M1B10M tokens

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

Where to run it5 hosts, cheapest first
Grok 4.1 Fast

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 4.1 Fast and Hy4 Preview?

Grok 4.1 Fast is developed by xAI while Hy4 Preview is developed by Tencent. 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 Hy4 Preview?

It depends on your use case. Grok 4.1 Fast and Hy4 Preview 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 Hy4 Preview on Rival?

This page shows a side-by-side comparison of Grok 4.1 Fast 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.

More comparisons

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Same lab, same size, long tail

  • Grok 4.1 Fast vs Grok 4.7Same lab
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  • Hy4 Preview vs Hy3Same lab
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  • Hy4 Preview vs Qwen3 30B A3BNew provider
  • Hy4 Preview vs Qwen3 30B A3B Instruct 2507New provider
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Model pages

  • Grok 4.1 Fast59 outputs, specs and price
  • Hy4 Preview71 outputs, specs and price
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