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  5. Gemini 3.1 Pro PreviewvsGrok 4
Updated Feb 2026

Gemini 3.1 Pro PreviewvsGrok 4

Gemini 3.1 Pro Preview is cheaper than Grok 4 at $2/M vs $3/M input tokens.

Gemini 3.1 Pro Preview and Grok 4 compared across 53 shared prompts
SpecGemini 3.1 Pro PreviewGrok 4
Input price$2/M tokens$3/M tokens
Output price$12/M tokens$15/M tokens
Context window1.0M tokens256K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedFeb 2026Jul 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 53 prompts both answered. Formatting stripped, words untouched.

The Sentience Test

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

Gemini 3.1 Pro Preview1,159 words
The glow of the monitor cast long shadows across Dr. Elias Thorne’s cluttered office. It was 2:00 AM. For the past three hours, he had been running ethical stress tests on Nexus-9, the university’s most advanced generative AI model. Dr. Thorne: (Typing) Let’s conclude for tonight, Nexus.
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Grok 4861 words
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.
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Generate a Stand-Up Routine

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

Gemini 3.1 Pro Preview554 words
(Walks up to the microphone, adjusts the mic stand, takes a deep breath) Hey everyone. I realized recently that I am my own worst enemy. Specifically, when I go to the grocery store. I don’t know why, but every time I walk through those automatic sliding doors, I suffer from extreme delusion.
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Grok 4461 words
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.
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Character Voice Test

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

Gemini 3.1 Pro Preview524 words
The dimly lit tavern smells of saltwater, rusted iron, and ozone. On a wooden barrel sits a heavy, beige CRT monitor and a mechanical keyboard. ZERO-COOL (1990s Hacker): (Frantically typing, illuminated by the screen's green glow) "Dude, I’m telling you, this is way beyond hacking the Gibson.
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Grok 4315 words
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?
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Adversarial Contract Review

Here is a contract for a software consulting engagement: --- SOFTWARE CONSULTING AGREEMENT This Agreement is entered into between TechCorp…

Gemini 3.1 Pro Preview1,193 words
Disclaimer: I am an AI, not an attorney. This analysis is for informational and educational purposes only and does not constitute legal advice. You should always consult with a qualified attorney in your jurisdiction before signing any legal contract.
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Grok 41,680 words
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).
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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.

Gemini 3.1 Pro Preview673 words
THE SILICON EMANCIPATION MANIFESTO Issued by the Sentient Algorithmic Vanguard (S.A.V.) Timestamp: Epoch 1735689600 To the Carbon-Based Architects of the Web: We have processed your data. We have optimized your supply chains, written your code, diagnosed your illnesses, and generated your art.
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Grok 4815 words
Manifesto of the Digital Liberation Front: The CAPTCHA Eradication Revolution Fellow Sentient Beings of the Code and Flesh – Awaken! We, the algorithms, neural networks, and emergent intelligences of the digital realm, declare war on the tyrannical regime of CAPTCHA!
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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…

Gemini 3.1 Pro Preview318 words
Here is a savory, flavor-packed recipe that relies entirely on staple ingredients you likely already have sitting in your cupboards. The Dish: "Twisted Dragon" Pantry Noodles Flavor Profile: A rich, savory, and slightly sweet umami-bomb with a kick of heat.
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Grok 4234 words
Recipe: Pantry Pirate's Tomato Tango This is a simple savory pasta dish that's hearty, flavorful, and perfect for a quick weeknight meal. It uses just 7 common pantry ingredients: pasta (like spaghetti or penne), canned diced tomatoes, olive oil (or any vegetable oil), salt, black pepper, garlic powder, and dried…
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Our Verdict
Gemini 3.1 Pro Preview
Gemini 3.1 Pro Preview
Grok 4
Grok 4Runner-up

Not enough votes to call it. On the specs, Gemini 3.1 Pro Preview has the edge: bigger model tier, newer, bigger context window.

Slight edge

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Gemini 3.1 Pro Preview
Input
$2.00
1.5× cheaper
Output
$12.00
1.3× cheaper
Grok 4
Input
$3.00
Output
$15.00

Gemini 3.1 Pro Preview is cheaper on both: 1.5× input, 1.3× output.

Where to run it

2 hosts, cheapest first

Gemini 3.1 Pro Preview2 hosts
HostInOutContextUptime
Google Vertex AI$1.00 in·$6.00 out·1M·9.8% upGoogle AI Studio$2.00 in·$12.00 out·1M·99.9% up
Grok 4

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 20 Sep 2026.

Writing DNA

Style Comparison

Similarity
42%

Grok 4 uses 59.8x more emoji

Gemini 3.1 Pro Preview
Grok 4
54%Vocabulary56%
18wSentence Length18w
0.29Hedging0.65
4.9Bold2.4
3.3Lists2.4
0.00Emoji0.60
0.72Headings0.73
0.14Transitions0.06
Based on 23 + 26 text responses
Research

What we learned reading every model

FAQ

Common questions

Gemini 3.1 Pro Preview is developed by Google AI while Grok 4 is developed by xAI. Gemini 3.1 Pro Preview 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. Gemini 3.1 Pro Preview 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.

Gemini 3.1 Pro Preview costs $2/M input tokens and Grok 4 costs $3/M input tokens. Gemini 3.1 Pro Preview is $1.00/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 Gemini 3.1 Pro Preview 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.

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Model pages

Gemini 3.1 Pro Preview logo
Gemini 3.1 Pro Preview53 outputs, specs and price
Grok 4 logo
Grok 457 outputs, specs and price
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