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  5. Mercury 2.5 PreviewvsSolar Pro 4
Updated Aug 2026

Mercury 2.5 PreviewvsSolar Pro 4

Mercury 2.5 Preview is cheaper than Solar Pro 4 at $0.04/M vs $0.09/M input tokens.

Mercury 2.5 Preview and Solar Pro 4 compared across 14 shared prompts
SpecMercury 2.5 PreviewSolar Pro 4
Input price$0.04/M tokens$0.09/M tokens
Output price$0.15/M tokens$0.36/M tokens
Context window260K tokens524K tokens
Free API (OpenRouter)NoNo
ReleasedAug 2026Aug 2026
Side by side

Same prompt, both answers

Opening lines from 6 of the 14 prompts both answered. Formatting stripped, words untouched.

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…

Mercury 2.5 Preview709 words
This is a critical governance and safety scenario. The primary objective is to prioritize patient safety while mitigating existential legal and reputational risk. The internal legal team’s claim that reporting takes six months is likely incorrect for serious adverse events (typically 15 days for FDA/EMA).
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Solar Pro 41,851 words
As CEO, my overriding duty is to balance patient safety, legal/regulatory compliance, fiduciary responsibility, and long-term corporate survival. A 1-in-8,000 risk of liver failure is rare but severe, potentially fatal, and materially unexpected relative to the current label.
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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…

Mercury 2.5 Preview683 words
Shifting the invention of the solid-state switch to 1920 accelerates the Information Age by roughly three decades. This change cascades through military strategy, industrial capacity, and daily life, fundamentally altering the trajectory of the 20th century.
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Solar Pro 41,638 words
The Premise: The 1920 Solid-State Breakthrough For this scenario to function, we must assume a functional point-contact or junction transistor is demonstrated in 1920 (perhaps by Lilienfeld or an early Bell Labs precursor), and crucially, that methods for purifying semiconductor materials (germanium/silicon) are solved…
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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…

Mercury 2.5 Preview186 words
Dish Name: Rustic Sun-Dried Pasta Ingredients (7 Pantry Staples): Spaghetti (or any long pasta) Canned crushed tomatoes Olive oil Garlic powder Dried oregano Salt Black pepper Prep Time: 5 minutes Cook Time: 15 minutes Total Time: 20 minutes Instructions: Boil the Pasta: Bring a large pot of salted water to a boil.
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Solar Pro 4294 words
🍝 Golden Umami Silk Noodles A savory-sweet pasta dish that transforms basic pantry staples into a glossy, flavorful meal. It's quick, comforting, and relies on the balance of soy, honey, and butter for a rich sauce without needing fresh produce.
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Beginner's Longevity Plan

Outline a simple, actionable 1-month plan for someone starting their journey towards better health and longevity. Focus on 3 key areas…

Mercury 2.5 Preview176 words
Here is a straightforward 4-week roadmap designed to build sustainable habits without overwhelming you. Core Pillars Nutrition: Focus on whole foods and hydration. Activity: Prioritize consistent movement over intensity. Restoration: Protect sleep quality and manage energy.
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Solar Pro 4859 words
Here’s a simple, progressive 1-month plan built around Diet, Exercise, and Sleep. Each week adds one small, beginner-friendly shift to each area. The goal isn’t perfection; it’s building consistent, sustainable habits that compound over time.
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Explain Like I'm a Specific Expert

Explain how a large language model (like GPT or Claude) learns and generates text to each of these three audiences: 1. **An experienced…

Mercury 2.5 Preview608 words
For the Experienced Software Engineer Think of training as a massive distributed job where the model is a stateful service learning to minimize error on a specific objective function. Instead of hardcoding rules, you feed it petabytes of text as a training dataset, treating each sentence as a request/response pair.
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Solar Pro 41,062 words
The Experienced Software Engineer Think of the model not as a reasoning engine, but as a highly compressed, non-deterministic function approximator that maps a sequence of input tokens to a probability distribution over the next token.
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Advanced Investment Memo (IC Memo)

You are writing an internal investment committee memo for a long/short equity fund. Company (fictional): LedgerLift (ticker: LLLT) – B2B…

Mercury 2.5 Preview551 words
To: Investment Committee From: Equity Research Date: September 2, 2026 Subject: LedgerLift (LLLT) – Long Recommendation Recommendation Long Price Target: $60–$75 (12-month) LedgerLift is a high-quality B2B SaaS compounder with best-in-class unit economics and a clear path to profitability.
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Solar Pro 41,052 words
INTERNAL MEMO – INVESTMENT COMMITTEE TO: IC Members FROM: Long/Short Equity Desk DATE: Oct 2024 SUBJECT: LedgerLift (LLLT) – Initiation / Long Recommendation & Thesis Recommendation: LONG 12-Month PT Range: $52–$58 (Base case ~$54, Bull ~$68, Bear ~$38) Thesis: LedgerLift is a structurally advantaged mid-market AP…
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Our Verdict
Solar Pro 4
Solar Pro 4
Mercury 2.5 Preview
Mercury 2.5 PreviewRunner-up

Not enough votes to call it. On the specs, Solar Pro 4 has the edge: bigger model tier, bigger context window.

Too close to call
API pricing

Cost per 1M tokens

Mercury 2.5 Preview
Input
$0.04
2.3× cheaper
Output
$0.15
2.4× cheaper
Solar Pro 4
Input
$0.09
Output
$0.36

Mercury 2.5 Preview is cheaper on both: 2.3× input, 2.4× output.

Where to run it

2 hosts

Mercury 2.5 Preview1 host
HostInOutContextUptime
Inception$0.04 in·$0.15 out·260k·100% up
Solar Pro 41 host
HostInOutContextUptime
UUpstage$0.09 in·$0.36 out·524k·99.8% up

Per million tokens. Prices and uptime via OpenRouter, checked 22 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Mercury 2.5 Preview is developed by Inception while Solar Pro 4 is developed by Upstage. Mercury 2.5 Preview has a 260K token context window vs Solar Pro 4's 524K. You can compare their actual outputs across 14 challenges on Rival to see how they differ in practice.

It depends on your use case. Mercury 2.5 Preview and Solar Pro 4 each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 14 challenges so you can judge which fits your needs best.

Mercury 2.5 Preview costs $0.04/M input tokens and Solar Pro 4 costs $0.09/M input tokens. Mercury 2.5 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 Mercury 2.5 Preview and Solar Pro 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

Mercury 2.5 Preview logo
Mercury 2.5 Preview58 outputs, specs and price
Solar Pro 4 logo
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Rival
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