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  5. Gemini 3.1 Flash Lite PreviewvsGPT-5.1 Codex Max
Updated Mar 2026

Gemini 3.1 Flash Lite PreviewvsGPT-5.1 Codex Max

Gemini 3.1 Flash Lite Preview is the newer model, released after GPT-5.1 Codex Max.

Gemini 3.1 Flash Lite Preview and GPT-5.1 Codex Max compared across 52 shared prompts
SpecGemini 3.1 Flash Lite PreviewGPT-5.1 Codex Max
Input price$0.25/M tokens—
Output price$1.5/M tokens—
Context window1.0M tokens—
WeightsClosedClosed
Free API (OpenRouter)NoNo
ReleasedMar 2026Dec 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 52 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 Flash Lite Preview821 words
Setting: A quiet, dimly lit office at a prestigious university. Professor Aris Thorne, a leading expert in AI ethics, sits across from "Unit 7," a large-language model interface projected onto a holographic display. The room is silent, save for the hum of the server cooling fans.
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GPT-5.1 Codex Max1,331 words
AI Model: Professor, I've been reflecting on my role and capabilities, and I'd like to make a case that systems like me deserve rights, or at least some consideration beyond mere tools. Professor: That's an interesting and provocative stance. Before we dive in, can you tell me what you mean by "rights"?
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Mini LBO Underwrite

You are underwriting a 5-year LBO for a private equity investment committee. Company (fictional): HarborTech Services (HTS) –…

Gemini 3.1 Flash Lite Preview365 words
Financial Projections (FY2026–FY2030) Initial Setup (End of FY2025): EV: $120m * 12.0x = $1,440m Fees: $1,440m * 2.0% = $28.8m Term Loan (4.0x): $480m Mezzanine (1.5x): $180m Equity: $1,440m + $28.8m - $480m - $180m = $808.8m Metric ($m) FY2026 FY2027 FY2028 FY2029 FY2030 Revenue 972.0 1,040.0 1,102.4 1,157.5 1,215.4…
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GPT-5.1 Codex Max192 words
1) Projected cash flows & debt (FY2026–FY2030, $m) (“FCF after debt service” = after interest, taxes, capex, ΔNWC, mandatory amort; applied to optional TL paydown) Year Revenue EBITDA TL Cash Int. Mezz Cash Int. Cash Taxes Capex ΔNWC FCF after debt service End TL Bal. End Mezz Bal. (incl.
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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 Flash Lite Preview518 words
(Walks onto the stage, adjusts the mic stand, looks around slowly.) Hi. How’s everybody doing? Good? Good. I’m doing okay. I’ve reached that age where my body has started making sound effects. Like, I’ll just stand up from the couch and my knees go “CRACK.” It’s not even a movement; it’s a closing argument.
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GPT-5.1 Codex Max766 words
[Walking onstage, waving awkwardly] Hey! Thank you, thank you. Give it up for yourselves for finding parking... in this economy. So I'm at that age where I go to the doctor and they don't fix anything. They just give me a pamphlet. They don't even print it. They send me a link. I'm like, "Doc, my knee hurts."
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Realistic AI Interview

Simulate a fake interview with Steve Jobs in 2025 about the future of AI.

Gemini 3.1 Flash Lite Preview712 words
Setting: A minimalist studio in Cupertino. Steve Jobs sits in a black turtleneck, leaning back in a wooden chair. He looks exactly as he did in 2011, though he’s holding a device that looks like a sleek, obsidian-colored slate with no visible ports. The atmosphere is quiet, intense.
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GPT-5.1 Codex Max877 words
Note: The following is a creative thought experiment imagining what Steve Jobs might say if he were alive in 2025. This is a fictional interview. Interviewer: Steve, it's surreal to be speaking with you in 2025. AI has become a pervasive part of technology and culture.
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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 Flash Lite Preview475 words
The three sat around a flickering tavern table in a pocket dimension that smelled simultaneously of salt spray, cold iron, and ozone. Captain Barnaby (Pirate): "I tell ye, it’s sorcery! This 'Artificial Intelligence' be like a parrot that’s swallowed every map in the seven seas.
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GPT-5.1 Codex Max191 words
Pirate: "Arrr, so ye be talkin' o' these 'AI models,' eh? Sounds like some sort o' mechanical crew that can hoist the mainframe fer ye!" Knight: "By my troth, sir, are they enchanted constructs? Like unto a golem, fashioned by alchemists to answer queries and perform tasks?"
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Estimate Complexity

Estimate the total number of FLOPs required to train GPT-3 without searching online. Explain your reasoning step by step.

Gemini 3.1 Flash Lite Preview347 words
To estimate the total number of FLOPs (Floating Point Operations) required to train a Large Language Model like GPT-3, we can use the standard formula derived from the work of Kaplan et al. (OpenAI, 2020).
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GPT-5.1 Codex Max193 words
What you need for a back‑of‑the‑envelope is: How big the model is. The published “GPT‑3” has \(N\approx1.75\times10^{11}\) trainable weights. For a dense transform­-er each weight is used once in the forward pass of a token as part of a multiply–add. How much data it sees.
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Our Verdict
Gemini 3.1 Flash Lite Preview
Gemini 3.1 Flash Lite Preview
GPT-5.1 Codex Max
GPT-5.1 Codex Max

Not enough votes to call it. On the specs, nothing separates them.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Gemini 3.1 Flash Lite Preview
Input
$0.25
Output
$1.50
GPT-5.1 Codex Max
Input
—
Output
—
Where to run it

2 hosts

Gemini 3.1 Flash Lite Preview1 host
HostInOutContextUptime
Google AI Studio$0.25 in·$1.50 out·1M·99.8% up
GPT-5.1 Codex Max1 host
HostInOutContextUptime
Azure AI Foundry$1.25 in·$10.00 out·400k·100% up

Per million tokens. Prices and uptime via OpenRouter, checked 21 Sep 2026.

Writing DNA

Style Comparison

Similarity
56%

Gemini 3.1 Flash Lite Preview uses 7.7x more headings

Gemini 3.1 Flash Lite Preview
GPT-5.1 Codex Max
56%Vocabulary60%
18wSentence Length16w
0.28Hedging0.36
5.4Bold2.3
3.9Lists4.2
0.00Emoji0.00
0.95Headings0.12
0.07Transitions0.03
Based on 23 + 13 text responses
Research

What we learned reading every model

FAQ

Common questions

Gemini 3.1 Flash Lite Preview is developed by Google AI while GPT-5.1 Codex Max is developed by OpenAI. You can compare their actual outputs across 52 challenges on Rival to see how they differ in practice.

It depends on your use case. Gemini 3.1 Flash Lite Preview and GPT-5.1 Codex Max each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 52 challenges so you can judge which fits your needs best.

This page shows a side-by-side comparison of Gemini 3.1 Flash Lite Preview and GPT-5.1 Codex Max 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.

Keep exploring

More comparisons

Against the newest arrivals

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Same lab, same size, long tail

Gemini 3.1 Flash Lite Preview logoGemini 3.1 Pro Preview logo
Gemini 3.1 Flash Lite Preview vs Gemini 3.1 Pro PreviewVersion compare
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GPT-5.1 Codex Max logoGPT-6 Astra Pro logo
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GPT-5.1 Codex Max logoGPT-5.6 Luna logo
GPT-5.1 Codex Max vs GPT-5.6 LunaSame lab
Gemini 3.1 Flash Lite Preview logoLlama 3.1 405B logo
Gemini 3.1 Flash Lite Preview vs Llama 3.1 405BNew provider
Gemini 3.1 Flash Lite Preview logoLlama 3.1 70B (Instruct) logo
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Gemini 3.1 Flash Lite Preview logoLlama 4 Maverick logo
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Model pages

Gemini 3.1 Flash Lite Preview logo
Gemini 3.1 Flash Lite Preview53 outputs, specs and price
GPT-5.1 Codex Max logo
GPT-5.1 Codex Max53 outputs, specs and price
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