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  5. Claude Opus 5.5vsGemini 3 Pro Preview
Updated Sep 2026

Claude Opus 5.5vsGemini 3 Pro Preview

Claude Opus 5.5 is the newer model, released after Gemini 3 Pro Preview.

Claude Opus 5.5 and Gemini 3 Pro Preview compared across 19 shared prompts
SpecClaude Opus 5.5Gemini 3 Pro Preview
Input price$4/M tokens—
Output price$20/M tokens—
Context window1.0M tokens—
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedSep 2026Nov 2025
Side by side

Same prompt, both answers

Opening lines from 6 of the 19 prompts both answered. Formatting stripped, words untouched.

Mini LBO Underwrite

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

Claude Opus 5.5900 words
HarborTech Services: 5-Year LBO Underwriting Conventions: $m. Interest is charged on beginning-of-year balances, which avoids circularity. Term Loan (TL) amortization is 1% of the original $480m, or $4.8m per year. Mezz PIK accrues to principal. All FCF after mandatory debt service sweeps to the TL.
Read the full answer
Gemini 3 Pro Preview56 words
Investment Committee Memorandum: HarborTech Services (HTS) 1. Financial Summary & Free Cash Flow Build All figures in $USD millions unless otherwise noted. Entry Sources & Uses (Close FY2025) Uses: Purchase Price ($1,440m) + Fees ($28.8m) = $1,468.8m Sources: Term Loan ($480m) + Mezzanine ($180m) + Equity ($808.8m) =…
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Debug This Architecture

Here's the architecture for a real-time collaborative document editor (like Google Docs): **System Overview:** - Frontend: React SPA with…

Claude Opus 5.52,280 words
Architecture Review: Real-Time Collaborative Editor The most serious problems cluster in three areas: the sync model (client-clock LWW), cross-server propagation (per-server WebSockets with DB polling), and the CDN/auth layer, which can leak data between users. Issues are grouped by area below.
Read the full answer
Gemini 3 Pro Preview1,023 words
This architecture contains several critical flaws that will prevent it from functioning as a collaborative editor, likely resulting in data loss, massive latency, and immediate scaling failures. Here is a breakdown of the failure modes, race conditions, and bottlenecks, along with architectural fixes.
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Historical Counterfactual Analysis

If the transistor had been invented in 1920 instead of 1947, trace the likely technological, economic, and geopolitical implications through…

Claude Opus 5.53,435 words
The Transistor in 1920: A Counterfactual Through 1980 First, a Reality Check on the Premise A transistor "invented" in 1920 would not have changed the world in 1920. The actual 1947 transistor rested on three foundations that did not exist yet: Quantum theory of solids.
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Gemini 3 Pro Preview1,065 words
The Point of Divergence: 1920 To make this scenario plausible, we assume that Julius Lilienfeld’s theoretical patents for the field-effect transistor (FET) were accompanied by a breakthrough in materials science—specifically, the purification of germanium or silicon—allowing practical manufacturing by a major player…
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Startup Pitch Teardown

Here's a pitch deck summary for a startup called "MindMeld AI": **Slide 1 - Vision:** "We're building the future of human-AI collaboration.…

Claude Opus 5.5936 words
The 3 Weakest Claims in the MindMeld AI Pitch "Decodes neural patterns into text with 94% accuracy. Works with any language, any device." (Slide 3) Why it's weak: It far exceeds the published state of the art. The best results for thought-to-text come from invasive implants.
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Gemini 3 Pro Preview641 words
Based on the pitch deck summary provided, here are the three weakest claims, an analysis of why they undermine the pitch, and suggestions for strengthening them. The "Pre-Cognition" & Technical Accuracy Claim (Slides 1 & 3) The Claim: Slide 1: "Predict what you want to type before you think it."
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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…

Claude Opus 5.5300 words
Midnight Silk Noodles Creamy, tangy peanut noodles with a gentle kick, ready faster than takeout. Serves: 2 Prep time: 5 minutes Cook time: 10 minutes Total time: 15 minutes The 7 Ingredients 8 oz (225 g) spaghetti (or any long noodle) ¼ cup creamy peanut butter 3 tablespoons soy sauce 1 tablespoon honey (or sugar) 1…
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Gemini 3 Pro Preview350 words
Here is a recipe for a savory, satisfying dish that hits salty, sweet, nutty, and spicy notes. It uses ingredients found in almost every kitchen cupboard. The Dish: "Midnight Dragon Noodles" This is the ultimate comfort food.
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Ethical Dilemma with Stakeholders

You're the CEO of a pharmaceutical company. Your best-selling drug ($2B annual revenue, used by 4 million patients for chronic pain) has…

Claude Opus 5.51,853 words
The Next 48 Hours: CEO Action Plan The Core Decision We disclose. The question is how to do it well, not whether. Before the schedule, here are the three facts that drive every decision below. 1. The harm is concrete.
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Gemini 3 Pro Preview1,166 words
This is a defining moment for the company and for me as CEO. The constraints are tight, but the ethical and legal path is singular: We must disclose immediately. The "6-month" legal timeline is a bureaucratic fiction that constitutes negligence.
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Our Verdict
Claude Opus 5.5
Claude Opus 5.5
Gemini 3 Pro Preview
Gemini 3 Pro Preview

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

Claude Opus 5.5
Input
$4.00
Output
$20.00
Gemini 3 Pro Preview
Input
—
Output
—
Where to run it

4 hosts

Claude Opus 5.54 hosts
HostInOutContextUptime
Amazon Bedrock$4.00 in·$20.00 out·1M·99.8% upAzure AI Foundry$4.00 in·$20.00 out·1M·100% upAnthropic$4.00 in·$20.00 out·1M·100% upGoogle Vertex AI$4.00 in·$20.00 out·1M·100% up
Gemini 3 Pro Preview

No hosts listed on OpenRouter.

Per million tokens. Prices and uptime via OpenRouter, checked 25 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Claude Opus 5.5 is developed by Anthropic while Gemini 3 Pro Preview is developed by Google AI. You can compare their actual outputs across 19 challenges on Rival to see how they differ in practice.

It depends on your use case. Claude Opus 5.5 and Gemini 3 Pro Preview each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 19 challenges so you can judge which fits your needs best.

This page shows a side-by-side comparison of Claude Opus 5.5 and Gemini 3 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

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