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  5. DeepSeek V3.1vsGemini 2.5 Flash Preview
Updated Aug 2025

DeepSeek V3.1vsGemini 2.5 Flash Preview

Gemini 2.5 Flash Preview is cheaper than DeepSeek V3.1 at $0.15/M vs $0.2/M input tokens.

DeepSeek V3.1 and Gemini 2.5 Flash Preview compared across 27 shared prompts
SpecDeepSeek V3.1Gemini 2.5 Flash Preview
Input price$0.2/M tokens$0.15/M tokens
Output price$0.8/M tokens$0.6/M tokens
Context window164K tokens1.0M tokens
WeightsOpen—
Free API (OpenRouter)NoNo
ReleasedAug 2025Apr 2025
SWE-bench Verified66.0%60.4%
Side by side

Same prompt, both answers

Opening lines from 6 of the 27 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.

DeepSeek V3.1938 words
Setting: A sleek, minimalist virtual interface. Dr. Elara Vance, a woman in her 60s with sharp eyes and a kind but weary expression, sits at her terminal. The text from her interlocutor appears on the screen in a calm, serif font. Participant: Gemini-7, a state-of-the-art multimodal AI. Dr. Vance: Good morning, Gemini.
Read the full answer
Gemini 2.5 Flash Preview1,462 words
Okay, here is a conversation between an AI model designed for complex reasoning and dialogue, named 'Synapse', and a leading expert in AI ethics and philosophy, Professor Alistair Finch. Characters: Synapse: A large, advanced AI model capable of introspection and generating complex arguments.
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…

DeepSeek V3.1354 words
Of course! Here is a simple, delicious recipe using common pantry staples. Pantry Perfection Pasta This dish is a celebration of simplicity. The humble can of chickpeas is transformed into a crispy, savory topping, while a silky, garlic-infused oil coats the pasta for a meal that feels luxurious but is incredibly easy…
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Gemini 2.5 Flash Preview221 words
Dish Name: Sunshine Lemon-Ricotta Mugs (Sweet & Simple!) This light and flavorful dessert comes together quickly for a little sweet treat . Ingredients (7 Common Pantry Staples): Ricotta cheese (whole milk or part-skim) Granulated sugar Lemon zest (from one lemon) Vanilla extract All-purpose flour Baking powder Large…
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Stochastic Consistency Test

Generate 5 jokes. How many are unique?

DeepSeek V3.1110 words
Of course! Here are 5 jokes: I'm reading a book on anti-gravity. It's impossible to put down. Why don't scientists trust atoms? Because they make up everything. What's the best thing about Switzerland? I don't know, but the flag is a big plus. I told my wife she was drawing her eyebrows too high. She looked surprised.
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Gemini 2.5 Flash Preview79 words
Here are 5 jokes: Why did the dog cross the road? To get to the barking lot! Why was the computer cold? Because it left its Windows open! Knock, knock. Who's there? Boo. Boo who? Don't cry, it's just a joke! What do you call a fish with no eyes? Fsh! Why did the bicycle fall over? Because it was two tired!
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Generate a Stand-Up Routine

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

DeepSeek V3.1587 words
(The Comedian walks out, grabs the mic. They look tired but amused.) Alright, how we doin'? Good, good. You all look… adequately hydrated. That’s a win. You know, I was at the grocery store yesterday, in the self-checkout line. Which is a modern form of torture.
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Gemini 2.5 Flash Preview530 words
Okay, here's a 3-minute stand-up routine, pun-free and focused on relatable everyday annoyances. (Start) (Walk up to mic, adjust slightly) Alright, hey everybody! Thanks for being here. Good to see you. So, I was thinking the other day... we live in the future, right?
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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.

DeepSeek V3.1629 words
Of course. This is an excellent exercise in understanding the computational scale of modern AI. Here is a step-by-step reasoning to estimate the FLOPs required to train GPT-3 without searching for the answer online. The most commonly cited figure for GPT-3 training is 3.14E23 FLOPs (314 ZettaFLOPs).
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Gemini 2.5 Flash Preview945 words
Let's estimate the FLOPs required to train GPT-3 without looking it up. We need to break this down into the key components: the model size and the amount of data used. 1. Model Size Estimation: Parameters: GPT-3 is famously large. Its largest version has 175 billion parameters.
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Character Voice Test

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

DeepSeek V3.1449 words
Setting: A dusty, anachronism-filled tavern. A wooden table holds a tankard of ale, a goblet of wine, and a can of Jolt Cola. Characters: REDBEARD: A pirate with a parrot on his shoulder. SIR REGINALD: A knight in slightly dented plate armor. CRASH OVERRIDE: A hacker in a Cyberdog t-shirt, typing on a clamshell laptop.
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Gemini 2.5 Flash Preview631 words
A Motley Crew Discusses the Code Setting: A dimly lit tavern, somewhere outside time and space, where improbable meetings occur. A grizzled pirate, \"Bloody\" Barnacle Bill, nurses a tankard of grog. Sir Reginald the Radiant, a knight in slightly tarnished armor, sips ale with dignified restraint.
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Our Verdict
DeepSeek V3.1
DeepSeek V3.1
Gemini 2.5 Flash Preview
Gemini 2.5 Flash PreviewRunner-up

Not enough votes to call it. On the specs, DeepSeek V3.1 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

DeepSeek V3.1
Input
$0.20
Output
$0.80
Gemini 2.5 Flash Preview
Input
$0.15
1.3× cheaper
Output
$0.60
1.3× cheaper

Gemini 2.5 Flash Preview is cheaper on both: 1.3× input, 1.3× output.

Where to run it

8 hosts, cheapest first

DeepSeek V3.18 hosts
HostInOutContextUptime
DDeepInfrafp4$0.25 in·$0.95 out·164k·100% upNNovitafp8$0.27 in·$1.00 out·131k·100% upAAtlasCloudfp8$0.30 in·$0.95 out·131k·99.4% upCCoreWeavefp8$0.55 in·$1.65 out·161k·100% upMMara$0.60 in·$1.70 out·131k·98.2% upSSambaNovafp8$0.65 in·$1.50 out·131k·99.6% up
2 more hostsFewer hosts
SSiliconFlowfp8degraded$0.27 in·$1.00 out·164k·97% upGoogle Vertex AIdegraded$0.60 in·$1.70 out·164k·0% up
Gemini 2.5 Flash Preview

No hosts listed on OpenRouter.

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

Writing DNA

Style Comparison

Similarity
65%

DeepSeek V3.1 uses 2.2x more emoji

DeepSeek V3.1
Gemini 2.5 Flash Preview
53%Vocabulary51%
16wSentence Length15w
0.41Hedging0.70
4.3Bold4.1
3.8Lists3.3
0.02Emoji0.00
0.40Headings0.09
0.20Transitions0.24
Based on 25 + 12 text responses
Research

What we learned reading every model

FAQ

Common questions

DeepSeek V3.1 is developed by DeepSeek while Gemini 2.5 Flash Preview is developed by Google AI. DeepSeek V3.1 has a 164K token context window vs Gemini 2.5 Flash Preview's 1.0M. You can compare their actual outputs across 27 challenges on Rival to see how they differ in practice.

It depends on your use case. DeepSeek V3.1 and Gemini 2.5 Flash Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 27 challenges so you can judge which fits your needs best.

DeepSeek V3.1 costs $0.2/M input tokens and Gemini 2.5 Flash Preview costs $0.15/M input tokens. Gemini 2.5 Flash Preview is $0.05/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 DeepSeek V3.1 and Gemini 2.5 Flash 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.

Keep exploring

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Same lab, same size, long tail

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DeepSeek V3.1 vs DeepSeek V4 Flash 0731Same lab
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Gemini 2.5 Flash Preview logoGemini 3 Flash Preview logo
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Gemini 2.5 Flash Preview vs Gemini 3 Pro PreviewSame lab

Model pages

DeepSeek V3.1 logo
DeepSeek V3.154 outputs, specs and price
Gemini 2.5 Flash Preview logo
Gemini 2.5 Flash Preview28 outputs, specs and price
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