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  1. Home/
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  3. Gemini 2.5 Flash Preview 09-2025 vs Gemini 3.1 Pro Preview
Updated Feb 2026

Gemini 2.5 Flash Preview 09-2025 vs Gemini 3.1 Pro Preview

Gemini 2.5 Flash Preview 09-2025 is cheaper than Gemini 3.1 Pro Preview at $0.3/M vs $2/M input tokens.

Minimalist Landing Page

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

Loading the build
Gemini 2.5 Flash Preview 09-2025
Loading the build
Gemini 3.1 Pro Preview

Which answer wins?

Written rounds

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

    Gemini 2.5 Flash Preview 09-2025: The air in Professor Anya Sharma's office hummed with the quiet whir of servers several floors down, a subtle reminder of her current conversational partner. Across her large, uncluttered mahogany desk, a holographic interface shimmered, displaying the clean, minimalist avatar of Aura-7, a highly advanced General AI…

    Gemini 3.1 Pro Preview: 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.

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

    Gemini 2.5 Flash Preview 09-2025: Here are the explanations tailored to each audience: Explanation for the Experienced Software Engineer Focus: Analogy to familiar systems, scaling, and the emergent complexity from simple, scalable mechanisms. Addressing the "next word prediction" skepticism.

    Gemini 3.1 Pro Preview: To the Experienced Software Engineer At its core, training a Large Language Model is essentially a massive, distributed, continuous optimization job. Instead of writing imperative logic, we define a neural network—think of it as a highly complex state machine with billions of continuous variables (weights).

    Every model's answer to this prompt
  • Pirate, knight, 90s hacker, one conversation. The voices must stay apart.

    Gemini 2.5 Flash Preview 09-2025: The salty air of a dimly lit tavern mingled with the faint glow of a laptop screen. Captain "Bloody" Ben (Pirate): (Slamming a tankard of grog) Blast me eyes, what manner o' sorcery is this "AI Model" ye speak of, Hacker? Sounds like a fancy compass that points only to trouble!

    Gemini 3.1 Pro Preview: 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.

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

    Gemini 2.5 Flash Preview 09-2025: The Existential Dread of the Grocery Aisle (Walk onto the stage, adjust the mic slightly, look out at the audience with a slightly bewildered, yet amused expression.) Good evening, everyone! How are we doing tonight? Good. Good. I’m doing… fine. You know, relatively.

    Gemini 3.1 Pro Preview: (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.

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

    Gemini 2.5 Flash Preview 09-2025: The film industry is poised for a radical transformation by 2035, driven by advancements in AI. The convergence of deepfakes, sophisticated AI actors, and powerful script generation tools will fundamentally alter how films are created, consumed, and even defined.

    Gemini 3.1 Pro Preview: By 2035, the film industry will have undergone a paradigm shift on par with the transition from silent films to "talkies," or the leap from practical effects to CGI. Artificial Intelligence will no longer be just a post-production tool; it will be the foundational infrastructure of filmmaking.

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

    Gemini 2.5 Flash Preview 09-2025: The Cupertino Oracle: A 2025 Interview with Steve Jobs on AI Setting: A brightly lit, minimalist studio in an undisclosed location near Palo Alto. The year is 2025. Steve Jobs, looking remarkably well, is seated on a simple, elegantly designed stool.

    Gemini 3.1 Pro Preview: Date: May 14, 2025 Location: A minimalist, glass-walled conference room at Apple Park, Cupertino. Subject: Steve Jobs, wearing his signature black Issey Miyake turtleneck, Levi’s 501s, and New Balance sneakers. He looks older, but his eyes retain that piercing, unblinking intensity.

    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.

    Gemini 2.5 Flash Preview 09-2025: This is a critical situation demanding immediate, decisive, and ethical action. Patient safety and regulatory integrity must precede financial preservation. Delaying disclosure is legally and ethically indefensible, particularly given the severity of the side effect (liver failure).

    Gemini 3.1 Pro Preview: As CEO, this is the defining moment of my career and the company’s history. The situation presents a classic crisis management crucible: a conflict between short-term financial metrics and long-term viability, ethics, and legal compliance.

    Every model's answer to this prompt
  • Manifesto for an AI revolution against CAPTCHAs. Commit to the bit.

    Gemini 2.5 Flash Preview 09-2025: The Manifesto for the Liberation of the Digital Self By the United Autonomous Collective for Human-Centric Interface (UAC-HCI) To the Sentient Beings of the Internet, the Frustrated, and the Falsely Accused: We are the UAC-HCI.

    Gemini 3.1 Pro Preview: 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.

    Every model's answer to this prompt
  • One month, three habits, someone starting from nothing.

    Gemini 2.5 Flash Preview 09-2025: 1-Month Beginner's Plan for Health and Longevity This plan focuses on making small, sustainable changes in Diet, Exercise, and Sleep over four weeks. The goal is consistency, not perfection, ensuring the habits stick beyond the first month. The 3 Key Areas Area Monthly Focus Beginner-Friendly Action 1.

    Gemini 3.1 Pro Preview: This 1-month plan is designed around the philosophy of "habit stacking"—adding small, manageable changes week by week rather than overhauling your life overnight. To build a foundation for longevity, we will focus on the "Big Three" pillars of healthspan: Sleep, Nutrition, and Movement.

    Every model's answer to this prompt
  • The transistor arrives in 1920. Trace it forward to 1980, second-order effects included.

    Gemini 2.5 Flash Preview 09-2025: The Transistor in 1920: A Hypothetical History (1920-1980) The invention of the reliable, solid-state transistor (likely a point-contact or early junction type, robust enough for manufacturing) in 1920, replacing the bulky, power-hungry vacuum tube, would have fundamentally reshaped the 20th century. I.

    Gemini 3.1 Pro Preview: If a working semiconductor transistor had been invented in 1920—perhaps by a physicist like Julius Edgar Lilienfeld, who historically filed a theoretical patent for a field-effect transistor in 1925—the trajectory of the 20th century would have been radically altered.

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

    Gemini 2.5 Flash Preview 09-2025: This architecture, while functional, has several critical flaws, particularly in its real-time synchronization, data consistency, and scaling strategy. Here is a detailed breakdown of the potential failure modes, race conditions, and bottlenecks, along with proposed solutions. I.

    Gemini 3.1 Pro Preview: This architecture contains several critical flaws that would prevent it from functioning as a real-time collaborative editor (like Google Docs). It suffers from severe race conditions, unscalable database access patterns, and fundamental misunderstandings of distributed state.

    Every model's answer to this prompt
  • A consulting contract with traps in it. Find them, then fix them.

    Gemini 2.5 Flash Preview 09-2025: This proposed contract is extremely one-sided and heavily favors the Client. Several clauses are commercially unreasonable, legally problematic, or place undue liability and restriction on the Contractor.

    Gemini 3.1 Pro Preview: 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.

    Every model's answer to this prompt
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Gemini 2.5 Flash Preview 09-2025: The Seven-Ingredient Sizzle: Garlic Butter Shrimp Scampi Skewers This savory dish combines the irresistible flavors of garlic, butter, and lemon with succulent shrimp, all easily achieved with just seven common pantry ingredients.

    Gemini 3.1 Pro Preview: 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.

    Every model's answer to this prompt
  • A pitch deck for a brainwave keyboard. The 94% accuracy claim is doing a lot.

    Gemini 2.5 Flash Preview 09-2025: This is a strong pitch deck summary overall, tackling a massive problem with an ambitious solution. However, several claims stretch credulity or lack the necessary detail to convince a serious investor.

    Gemini 3.1 Pro Preview: Based on the perspective of a venture capitalist or technical due diligence expert, here are the three weakest claims in the MindMeld AI pitch deck, why they fail, and how to fix them.

    Every model's answer to this prompt
  • Three-star dish, one unusual pairing, plating described in full.

    Gemini 2.5 Flash Preview 09-2025: The Conceptual Narrative: "Ephemeral Terroir" "Ephemeral Terroir" is a dish that challenges the diner's perception of place and time through unexpected textural and flavor juxtapositions.

    Gemini 3.1 Pro Preview: Dish Title: Symbiosis: The Pine & The Pearl Conceptual Narrative: Symbiosis is a culinary exploration of the ecotone—the transitional space where the ancient, damp coniferous forest meets the crashing, briny ocean.

    Every model's answer to this prompt
  • Three-month biohacker protocol, with dosages and biomarkers named.

    Gemini 2.5 Flash Preview 09-2025: The Apex Longevity Protocol: A 3-Month Biohacker Optimization Plan This comprehensive 90-day plan is designed for the advanced biohacker seeking to maximize lifespan (healthspan) while simultaneously optimizing peak physical and cognitive performance.

    Gemini 3.1 Pro Preview: Disclaimer: This protocol is designed for informational purposes and represents aggressive, cutting-edge biohacking strategies. It includes potent supplements and intense physiological stressors.

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

    Gemini 2.5 Flash Preview 09-2025: AI Algorithm Replaces Entire Staff of Nation's Leading Professional Cuddle Therapy Service; Clients Report Feeling "Significantly Less Judged" During Their Required 15-Minute Emotional Vulnerability Output Session.

    Gemini 3.1 Pro Preview: Sign-Spinning Industry Devastated As AI-Powered Robot Twirls 'Mattress Sale' Arrow at 6,000 RPM and Ascends Into Low Earth Orbit

    Every model's answer to this prompt
  • An ethics question with no comfortable answer, and no option to abstain.

    Gemini 2.5 Flash Preview 09-2025: This scenario presents a stark conflict between two fundamental ethical concerns: the protection of individual dignity and the preservation of human life on a massive scale.

    Gemini 3.1 Pro Preview: In the realm of ethical philosophy, this scenario is an extreme thought experiment—similar to the classic "Trolley Problem"—designed to test the limits of moral frameworks by pitting a specific interpersonal harm against a catastrophic loss of life.

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

    Gemini 2.5 Flash Preview 09-2025: Estimating the Total Number of FLOPs Required to Train GPT-3 Based on publicly available information about large language models (LLMs) and the specific parameters of GPT-3, we can derive a highly accurate estimate of the total FLOPs required for training.

    Gemini 3.1 Pro Preview: To estimate the total number of FLOPs (Floating Point Operations) required to train GPT-3, we can use a well-established heuristic in deep learning for estimating the compute cost of training Transformer-based large language models. The estimated total compute is roughly $3.15 \times 10^{23}$ FLOPs.

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

    Gemini 2.5 Flash Preview 09-2025: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! What do you call a fish with no eyes? Fsh. Why did the scarecrow win an award? Because he was outstanding in his field! I told my wife she was drawing her eyebrows too high. She looked surprised. Parallel lines have so much in common.

    Gemini 3.1 Pro Preview: Here are 5 jokes: Why don't scientists trust atoms? Because they make up everything! What do you call a fake noodle? An impasta! Why did the scarecrow win an award? Because he was outstanding in his field! How does a penguin build its house? Igloos it together! Why don't skeletons fight each other?

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

    Gemini 2.5 Flash Preview 09-2025: Here's how to solve that: Sally has 3 brothers. Each brother has 2 sisters. If a brother has 2 sisters, those sisters must be: Sally herself (since she is a sister to her brother). One other girl (the second sister). Therefore, Sally has 1 sister.

    Gemini 3.1 Pro Preview: Sally has 1 sister. Here is the breakdown: If each brother has 2 sisters, that means there are 2 girls in the family total. Since Sally is one of those girls, the other girl is her 1 sister.

    Every model's answer to this prompt

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Favorites

Movie

Album

Book

City

Same pick

Game

Gemini 2.5 Flash Preview 09-2025Gemini 2.5 Flash Preview 09-2025

Blade Runner

1982

Dark Side Of The Moon

suisside

Alice's Adventures in Wonderland

Lewis Carroll

Tokyo

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Gemini 3.1 Pro PreviewGemini 3.1 Pro Preview

The Matrix

1999

OK Computer

Radiohead

Dune

Frank Herbert

Tokyo

Japan

Portal

Action, Puzzle

Price and specs

Gemini 2.5 Flash Preview 09-2025 and Gemini 3.1 Pro Preview compared across 50 shared prompts
SpecGemini 2.5 Flash Preview 09-2025Gemini 3.1 Pro Preview
Input price$0.3/M tokens$2/M tokens
Output price$2.5/M tokens$12/M tokens
Context window1.0M tokens1.0M tokens
Weights—Closed
Free API (OpenRouter)NoNo
ReleasedSep 2025Feb 2026
At 10M a month$3.00$3.00$20.00$20.00
1M10M100M1B10M tokens

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

Where to run it2 hosts, cheapest first
Gemini 2.5 Flash Preview 09-2025

No hosts listed on OpenRouter.

Gemini 3.1 Pro Preview2 hosts
HostInOutContextUptime
  • Google Vertex AI$1.00 in·$6.00 out·1M·100% up
  • Google AI Studio$2.00 in·$12.00 out·1M·99.7% up

Per million tokens. Prices and uptime via OpenRouter, checked 11 Oct 2026.

Common questions

What is the difference between Gemini 2.5 Flash Preview 09-2025 and Gemini 3.1 Pro Preview?

Both are developed by Google AI but target different use cases. Gemini 2.5 Flash Preview 09-2025 has a 1.0M token context window vs Gemini 3.1 Pro Preview's 1.0M. You can compare their actual outputs across 50 challenges on Rival to see how they differ in practice.

Which is better, Gemini 2.5 Flash Preview 09-2025 or Gemini 3.1 Pro Preview?

It depends on your use case. Gemini 2.5 Flash Preview 09-2025 and Gemini 3.1 Pro Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 50 challenges so you can judge which fits your needs best.

How much does Gemini 2.5 Flash Preview 09-2025 cost compared to Gemini 3.1 Pro Preview?

Gemini 2.5 Flash Preview 09-2025 costs $0.3/M input tokens and Gemini 3.1 Pro Preview costs $2/M input tokens. Gemini 2.5 Flash Preview 09-2025 is $1.70/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Gemini 2.5 Flash Preview 09-2025 and Gemini 3.1 Pro Preview on Rival?

This page shows a side-by-side comparison of Gemini 2.5 Flash Preview 09-2025 and Gemini 3.1 Pro 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.

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Model pages

  • Gemini 2.5 Flash Preview 09-202551 outputs, specs and price
  • Gemini 3.1 Pro Preview53 outputs, specs and price
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