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  1. Home/
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  3. Grok 4.20 Beta vs Optimus Alpha
Updated Mar 2026

Grok 4.20 Beta vs Optimus Alpha

Grok 4.20 Beta has a larger context window than Optimus Alpha (2.0M tokens vs 1.0M tokens).

Minimalist Landing Page

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

Loading the build
Grok 4.20 Beta
Loading the build
Optimus Alpha

Which answer wins?

Written rounds

8 prompts
  • An AI argues for its own rights against an ethics professor. Same model writes both.

    Grok 4.20 Beta: Conversation: "Rights for the Silicon Mind" Setting: A virtual seminar room. Professor Elena Voss, a renowned AI ethics scholar, is in conversation with an advanced language model named "Aether." Prof. Voss: Thank you for joining me today, Aether.

    Optimus Alpha: AI Model: Good afternoon, Professor Lee. I want to discuss the prospect that I, as an artificial intelligence, deserve certain rights. Professor Lee: That's an interesting proposition. Let me ask: On what basis do you believe you deserve rights?

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

    Grok 4.20 Beta: Stand-up Routine: "Adulting is a Scam" (Lights up. Comedian walks out with a coffee cup, takes a sip, immediately looks disappointed.) You ever notice how nobody warns you that being an adult is just childhood with bills and worse snacks?

    Optimus Alpha: Absolutely! Here's a 3-minute stand-up routine with no puns—just observational and relatable humor: You ever try to get healthy, but your body's like, "Whoa, whoa... calm down, superhero." I joined a gym—first time walking in, the treadmill looked at me like, "We both know you're here for the wifi."

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

    Grok 4.20 Beta: Fake Interview: Steve Jobs in 2025 Interviewer: Mr. Jobs, thank you for sitting down with us. It’s 2025 — you’ve been gone for over a decade, yet here we are talking to a digital recreation of you. How does that feel? Steve Jobs: (smiling that half-smirk) It feels like the ultimate irony.

    Optimus Alpha: Interviewer: Steve, it's surreal and inspiring to imagine talking to you in 2025. The world is buzzing about AI. How do you see AI impacting society? Steve Jobs: Thank you. You know, when we built the Mac, our goal was to put power in people's hands.

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

    Grok 4.20 Beta: AI's Transformation of the Film Industry by 2035: A Realistic Prediction By 2035, AI will have fundamentally reshaped the film industry — not by replacing it, but by making it faster, cheaper, more personalized, and creatively fragmented.

    Optimus Alpha: By 2035, AI is set to fundamentally transform the film industry in several interconnected ways: 1. Deepfakes & AI-driven Visual Effects: Virtually unlimited creative freedom: AI-powered deepfakes will allow seamless, photorealistic de-aging, resurrection of deceased actors, and transformative performance capture.

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

    Grok 4.20 Beta: Sally has 2 sisters. Explanation: Sally is a girl, so she is one of the sisters. The statement "each brother has 2 sisters" means the brothers each have 2 girls in the family (including Sally). Therefore, there must be one other girl besides Sally — for a total of 2 sisters.

    Optimus Alpha: Let's break down the problem: Sally is a girl. Sally has 3 brothers. Each brother has 2 sisters. Let's analyze: Sally's siblings: 3 brothers (let's call them B1, B2, B3) Sally herself The brothers' sisters: Each brother has 2 sisters. Who are the possible sisters for each brother? Sally is a sister to each brother.

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

    Grok 4.20 Beta: Here are 5 jokes: Why don't skeletons fight each other? They don't have the guts. Why did the scarecrow win an award? He was outstanding in his field. Why don't eggs tell jokes? They'd crack each other up. Why did the bicycle fall over? It was two tired. Why did the math book look sad? Because it had too many problems.

    Optimus Alpha: Here are 5 jokes: Why did the scarecrow win an award? Because he was outstanding in his field! Why don't scientists trust atoms? Because they make up everything! Why did the bicycle fall over? Because it was two-tired! What do you call fake spaghetti? An impasta! I used to play piano by ear, but now I use my hands.

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

    Grok 4.20 Beta: Estimated total FLOPs for training GPT-3: ~3.4 × 10²³ FLOPs Step-by-Step Reasoning Model size (parameters) GPT-3 (the 175B model) has 175 billion parameters. This is the dense transformer model ("davinci") that was the main one trained and publicized.

    Optimus Alpha: Let's walk through an estimation of how many FLOPs were required to train GPT-3, using only reasoning and not searching for the exact numbers. Step 1: Understand Model Size GPT-3 (the original) had 175 billion parameters.

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

    Grok 4.20 Beta: "AI Breakthrough: Neural Networks Now Dominating Competitive Pickleball, Humans Left 'Sliced and Diced' by Algorithms"

    Optimus Alpha: AI Now Dominates Competitive Sheep Herding, Local Border Collies Seek Retraining in Data Science

    Every model's answer to this prompt

Price and specs

Not enough votes to call it. On the specs, Grok 4.20 Beta has the edge: bigger model tier, newer, bigger context window, major provider backing.

Grok 4.20 Beta and Optimus Alpha compared across 17 shared prompts
SpecGrok 4.20 BetaOptimus Alpha
Input price$2/M tokens—
Output price$6/M tokens—
Context window2.0M tokens1.0M tokens
WeightsClosed—
Free API (OpenRouter)No—
ReleasedMar 2026Apr 2025
At 10M a month$20.00$20.00–not listed
1M10M100M1B10M tokens

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

Where to run it1 host
Grok 4.20 Beta1 host
HostInOutContextUptime
  • xAI$1.25 in·$2.50 out·2M·100% up
Optimus Alpha

No hosts listed on OpenRouter.

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

Common questions

What is the difference between Grok 4.20 Beta and Optimus Alpha?

Grok 4.20 Beta is developed by xAI while Optimus Alpha is developed by OpenRouter. Grok 4.20 Beta has a 2.0M token context window vs Optimus Alpha's 1.0M. You can compare their actual outputs across 17 challenges on Rival to see how they differ in practice.

Which is better, Grok 4.20 Beta or Optimus Alpha?

It depends on your use case. Grok 4.20 Beta and Optimus Alpha each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 17 challenges so you can judge which fits your needs best.

How can I compare Grok 4.20 Beta and Optimus Alpha on Rival?

This page shows a side-by-side comparison of Grok 4.20 Beta and Optimus Alpha 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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  • Optimus Alpha vs GPT-6.1 SolLanded Sep 2026

Same lab, same size, long tail

  • Grok 4.20 Beta vs Grok 4.20 Multi-Agent BetaVersion compare
  • Grok 4.20 Beta vs Grok 4.7Same lab
  • Optimus Alpha vs Ox AlphaSame lab
  • Optimus Alpha vs OpenRouter Fusion · Budget (Jun 2026)Same lab
  • Grok 4.20 Beta vs GPT-5.1 Codex MaxSame size
  • Grok 4.20 Beta vs GPT-5.1-Codex-MiniSame size
  • Grok 4.20 Beta vs GPT-5.2Same size
  • Grok 4.20 Beta vs GPT-5.2 ChatNew provider

Model pages

  • Grok 4.20 Beta53 outputs, specs and price
  • Optimus Alpha19 outputs, specs and price
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Explore all of Rival

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