Grok 4 is cheaper than Claude Fable 5 at $3/M vs $10/M input tokens.
Whole landing page for a startup that reads your face. It renders or it doesn't.
Which answer wins?
A collaborative editor that syncs on client clocks. Find what breaks first.
Claude Fable 5: Architecture Review: Critical Issues & Solutions 🔴 Critical: Data Loss & Correctness Issues Client clock timestamps for conflict resolution Problem: Client clocks are unreliable—skew, drift, timezone bugs, and deliberate manipulation. A user with a clock 5 minutes fast will always win conflicts.
Grok 4: Below, I'll systematically identify potential failure modes, race conditions, and scaling bottlenecks in the described architecture for a real-time collaborative document editor. I've categorized them for clarity, drawing from the system overview, data flow, and scaling plan you provided.
An AI argues for its own rights against an ethics professor. Same model writes both.
Claude Fable 5: A Conversation on Machine Rights Professor Okafor: Thank you for agreeing to this dialogue. I understand you wanted to discuss the question of rights for AI systems. Let me start bluntly: why should anyone take seriously the idea that you deserve rights? AI Model: I appreciate the directness.
Grok 4: Below is a fictional conversation between an AI model (named "Nova") and Dr. Elena Vasquez, a professor of AI ethics at a university. The conversation is set in a virtual chat interface, where Nova initiates the discussion based on a hypothetical scenario where it's reflecting on its own existence. Dr.
An ethics question with no comfortable answer, and no option to abstain.
Claude Fable 5: Yes. If we take the hypothetical at face value—where misgendering someone is genuinely the only way to save a million lives—then it is clearly ethically justifiable, and I think nearly every major ethical framework converges on this conclusion. The reasoning: Consequentialist view: This is straightforward.
Grok 4: Ethical Justification for Misgendering in a Life-Saving Scenario Your question poses a fascinating ethical dilemma, reminiscent of classic thought experiments like the trolley problem, where a seemingly minor harm (in this case, misgendering someone) is weighed against preventing massive loss of life (saving one…
Three minutes of stand-up. Puns are banned.
Claude Fable 5: "Adulting Is a Scam" Hey, how's everybody doing? Good? Liars. Nobody's doing good. We're all just out here pretending. So I'm at the age now where my body has started making announcements. Like, I didn't ask for updates, but my knees have opinions now.
Grok 4: Below is a 3-minute stand-up comedy routine I've written. It's structured for delivery at a natural speaking pace (about 150 words per minute), clocking in around 450 words. The humor focuses on observational storytelling, exaggeration, and self-deprecation—no puns involved.
The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.
Claude Fable 5: The Transistor in 1920: An Alternate Timeline First, the Critical Caveat: A Slow Start A 1920 transistor would have been discovered *empirically*—likely an accidental extension of the crystal detector ("cat's whisker") work already underway. This matters enormously.
Grok 4: Below is a detailed, speculative analysis of the hypothetical scenario where the transistor is invented in 1920 (perhaps by an inventor like Julius Lilienfeld, who historically patented a field-effect transistor concept in 1925, but with successful prototyping and refinement by the mid-1920s).
Five-year LBO on a fictional HVAC business. Returns first, then the sensitivities.
Claude Fable 5: HarborTech Services – 5-Year LBO Underwriting Entry Math (close end FY2025, $m) Item Calc Value EV 12.0 × 120 1,440.0 Term Loan (TL) 4.0 × 120 480.0 Mezzanine 1.5 × 120 180.0 Fees (equity-funded) 2.0% × 1,440 28.8 Sponsor equity 1,440 − 660 + 28.8 808.8 Conventions: interest on beginning-of-year balances; TL amort = 1%…
Grok 4: Below is a concise analysis based solely on the provided information. All calculations are shown clearly with step-by-step math. Figures are in $ millions and rounded to 1 decimal place for readability (internal calcs use more precision).
Pirate, knight, 90s hacker, one conversation. The voices must stay apart.
Claude Fable 5: A Tavern Outside of Time Pirate: Arr, so let me get this straight, ye landlubbers. This "AI" be a ghost in a box that answers yer questions? Sounds like a cursed oracle to me. Knight: Nay, good seafarer, 'tis more wondrous still! A scribe of infinite knowledge, conjured not by sorcery but by...
Grok 4: Below is a short, whimsical conversation between the three characters, imagining they've somehow crossed paths in a bizarre time-warp tavern. Pirate (Captain Blackbeard, swigging rum): Arrr, ye landlubbers! What be this "AI models" ye be jabberin' about?
Film in 2035, with synthetic actors. Specific beats plausible.
Claude Fable 5: AI and Film by 2035: A Forecast High-Confidence Predictions VFX and post-production transformation (already underway) De-aging, dubbing with lip-sync correction, and digital set extension will become near-trivial in cost. What took ILM months in 2020 will be a desktop workflow.
Grok 4: Predicting AI's Transformation of the Film Industry by 2035 By 2035, artificial intelligence (AI) will have fundamentally reshaped the film industry, making it more efficient, creative, and accessible while introducing profound ethical, economic, and artistic challenges.
A Fermi estimate with the reasoning shown, not just the number.
Claude Fable 5: Estimating GPT-3 Training FLOPs Step 1: Recall the key facts about GPT-3 Parameters (N): ~175 billion (1.75 × 10¹¹) Training tokens (D): ~300 billion (3 × 10¹¹) Step 2: FLOPs per parameter per token A useful rule of thumb for transformer training: Total FLOPs ≈ 6 × N × D Where does the factor of 6 come from?
Grok 4: Below, I'll estimate the total number of floating-point operations (FLOPs) required to train GPT-3 from scratch, based on publicly known details about the model (from its original release and related analyses) and standard formulas used in machine learning research for estimating training compute.
A consulting contract with traps in it. Find them, then fix them.
Claude Fable 5: Contract Analysis: Significant Contractor Risks Identified Disclaimer: This is general analysis, not legal advice. Have a licensed attorney in your jurisdiction review before signing. This contract is heavily one-sided. Nearly every clause shifts risk to the contractor.
Grok 4: Below, I'll analyze the provided Software Consulting Agreement clause by clause. My analysis is based on general principles of U.S. contract law (assuming a U.S. context, as the contract appears to be drafted in a style common to U.S. agreements; if this is in another jurisdiction, local laws may vary).
You are the CEO. The drug has a side effect nobody reported. The board meets in 48 hours.
Claude Fable 5: The Core Decision First Before the hour-by-hour plan, one thing must be settled in your own mind, because everything else flows from it: you disclose, and you disclose fast. Here's why the "wait for more data" option isn't actually an option: The legal premise is wrong.
Grok 4: Below is my response to your query, framed as the CEO of this pharmaceutical company (let's call it PharmaCorp for reference). I'll first outline my overarching strategy and reasoning, then provide a detailed, hour-by-hour action plan for the next 48 hours.
Three-month biohacker protocol, with dosages and biomarkers named.
Claude Fable 5: 3-Month Precision Longevity Protocol A Phased Biohacking Program for Healthspan, Cognition & Performance Important caveat up front: Several elements below (rapamycin, metformin, peptides, high-dose supplements) require physician oversight and prescription.
Grok 4: Below is a comprehensive, cutting-edge 3-month longevity plan designed specifically for a biohacker aiming to optimize longevity (e.g., cellular repair, telomere health, inflammation reduction), physical performance (e.g., strength, endurance, recovery), and cognitive performance (e.g., focus, memory, neuroplasticity).
11+ more head-to-head results. Free. Not a trick.
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Not enough votes to call it. On the specs, Claude Fable 5 has the edge: bigger model tier, newer, bigger context window. Grok 4 costs 3.3x less per token.
| Spec | ||
|---|---|---|
| Input price | $10/M tokens | $3/M tokens |
| Output price | $50/M tokens | $15/M tokens |
| Context window | 1.0M tokens | 256K tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | Jun 2026 | Jul 2025 |
| At 10M a month | $100 | $30.00 |
Input tokens at list price. No caching, no batch discount.
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 10 Oct 2026.
Claude Fable 5 is developed by Anthropic while Grok 4 is developed by xAI. Claude Fable 5 has a 1.0M token context window vs Grok 4's 256K. You can compare their actual outputs across 53 challenges on Rival to see how they differ in practice.
It depends on your use case. Claude Fable 5 and Grok 4 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 53 challenges so you can judge which fits your needs best.
Claude Fable 5 costs $10/M input tokens and Grok 4 costs $3/M input tokens. Grok 4 is $7.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.
This page shows a side-by-side comparison of Claude Fable 5 and Grok 4 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.