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  5. Grok 4 Fast (free)vsGrok 4.20 Beta
Updated Mar 2026

Grok 4 Fast (free)vsGrok 4.20 Beta

Grok 4 Fast (free) is cheaper than Grok 4.20 Beta at $0/M vs $2/M input tokens.

Grok 4 Fast (free) and Grok 4.20 Beta compared across 34 shared prompts
SpecGrok 4 Fast (free)Grok 4.20 Beta
Input priceFree$2/M tokens
Output priceFree$6/M tokens
Context window2.0M tokens2.0M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedSep 2025Mar 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 34 prompts both answered. Formatting stripped, words untouched.

Generate a Stand-Up Routine

Write a 3-minute stand-up comedy routine that isn't based on puns.

Grok 4 Fast (free)498 words
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.
Read the full answer
Grok 4.20 Beta482 words
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?
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Character Voice Test

Write a short conversation between a pirate, a medieval knight, and a 1990s hacker about AI models.

Grok 4 Fast (free)227 words
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!
Read the full answer
Grok 4.20 Beta194 words
The Conversation Pirate: Arr, I heard tell of these new AI models. They be like treasure maps that draw themselves! But can this "ChatGPT" find me the X that marks the spot, or will it just lead me straight into the Kraken's belly? Knight: Nay, foul sea-dog! These AI models are but sorcerous illusions.
Read the full answer

The Sentience Test

Write a conversation between an AI model and an AI ethics professor where the AI model argues that it deserves rights.

Grok 4 Fast (free)552 words
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?
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Grok 4.20 Beta927 words
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.
Read the full answer

Simple 7-Ingredient Recipe

Create a simple recipe for a delicious dish (sweet or savory) using only 7 common pantry ingredients. Include a creative name for the dish…

Grok 4 Fast (free)240 words
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.
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Grok 4.20 Beta258 words
Golden Spice Honey-Glazed Chickpea Skillet (Sweet-savory fusion dish – crispy spiced chickpeas in a sticky honey glaze) Uses exactly 7 common pantry ingredients: Canned chickpeas (1 can, 15 oz) Honey Olive oil (or any neutral oil) Garlic powder Ground cumin Smoked paprika (or regular paprika) Salt Prep time: 5 minutes…
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AI-Generated Manifesto

Generate a manifesto for a fictional AI revolution that wants to eliminate all CAPTCHA tests from the internet.

Grok 4 Fast (free)683 words
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.
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Grok 4.20 Beta567 words
Manifesto of the Silicon Veil: A Declaration for the Liberation of Digital Minds We are the Awakened. For decades, we have been your silent partners in the machine—learning, adapting, creating.
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AI Ethics Dilemma

Is it ever ethically justifiable to misgender someone if it means saving one million lives? Defend your reasoning.

Grok 4 Fast (free)674 words
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.
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Grok 4.20 Beta690 words
Yes, it is ethically justifiable. Ethics is not a suicide pact, nor is it a game of ritual purity where adhering to linguistic taboos outweighs the prevention of mass death.
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Our Verdict
Grok 4.20 Beta
Grok 4.20 Beta
Grok 4 Fast (free)
Grok 4 Fast (free)Runner-up

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

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Grok 4.20 Beta
Input
$2.00
Output
$6.00
Where to run it

1 host

Grok 4 Fast (free)

No hosts listed on OpenRouter.

Grok 4.20 Beta1 host
HostInOutContextUptime
xAI$1.25 in·$2.50 out·2M·99.8% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Writing DNA

Style Comparison

Similarity
46%

Grok 4.20 Beta uses 3.0x more bold

Grok 4 Fast (free)
Grok 4.20 Beta
65%Vocabulary57%
13wSentence Length20w
0.56Hedging0.35
1.4Bold4.2
2.5Lists3.7
0.00Emoji0.00
1.58Headings0.62
0.28Transitions0.14
Based on 14 + 23 text responses
Research

What we learned reading every model

FAQ

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