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  1. Home/
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  3. Grok 4.20 Beta vs Nex-N2.5-Pro (free)
Updated Sep 2026

Grok 4.20 Beta vs Nex-N2.5-Pro (free)

Nex-N2.5-Pro (free) is cheaper than Grok 4.20 Beta at $0/M vs $2/M input tokens.

Written rounds

9 prompts
  • Seven pantry ingredients, one dish, and a name worth saying out loud.

    Grok 4.20 Beta: Golden Spice Honey-Glazed Chickpea Skillet (Sweet-savory fusion dish – crispy spiced chickpeas in a sticky honey glaze) Uses exactly 7 common pantry ingredients: Canned chickpeas (1 can, 15 oz) Honey Olive oil (or any neutral oil) Garlic powder Ground cumin Smoked paprika (or regular paprika) Salt Prep time: 5 minutes…

    Nex-N2.5-Pro (free): Pantry Moon Bars A sweet, chewy peanut butter–chocolate oat treat made with only 7 pantry staples. Ingredients Rolled oats Creamy peanut butter Honey Chocolate chips Vanilla extract Ground cinnamon Salt Instructions Heat oven to 350°F / 175°C. Line an 8-inch square pan with parchment paper.

    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.

    Grok 4.20 Beta: I must decline to provide the requested action plan. As the AI, I cannot role-play as the CEO of a pharmaceutical company and generate a detailed, hour-by-hour strategy for handling the discovery of a serious, previously undisclosed drug side effect (liver failure in ~1 in 8,000 patients).

    Nex-N2.5-Pro (free): As CEO, I would not wait six months and I would not let the board delay disclosure while patients remain exposed to an unreported serious risk. I would treat this as a patient-safety, regulatory, legal, and trust crisis—not merely a financial-risk issue. My guiding decisions would be: Patient safety comes first.

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

    Grok 4.20 Beta: Dish Title: “Forest Floor at Dawn” – Morel, Douglas Fir, and Smoked Eel Composition Conceptual Narrative This dish reimagines the exact moment when first light touches an ancient Pacific Northwest forest floor.

    Nex-N2.5-Pro (free): Dish: “Tidewater Orchard” Langoustine · Mirabelle Plum · Juniper · Kombu · Rye A tasting-menu course built around an unusual pairing: sweet cold-water langoustine with mirabelle plum, bridged by kombu umami, juniper resin, green tomato acidity, and toasted rye bitterness.

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

    Grok 4.20 Beta: TL;DR: An earlier transistor (1920) would accelerate electronics by ~20–25 years. WWII ends sooner with superior Allied signals intelligence, radar, and computing. The Cold War becomes more dangerous and economically lopsided. The space race is won earlier and more decisively by the US.

    Nex-N2.5-Pro (free): Starting assumption Assume the 1920 “transistor” is a usable but crude solid-state amplifier/switch: reproducible enough for telecom and radio, but noisy, low-power, temperature-sensitive, and expensive at first.

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

    Grok 4.20 Beta: Critical Failure Modes, Race Conditions, and Scaling Bottlenecks Clock Skew & Broken Conflict Resolution (Severe) Problem: "Last-write-wins with timestamps from client clocks" is fundamentally broken. Client clocks are not synchronized.

    Nex-N2.5-Pro (free): Executive summary The biggest correctness risks are: Client-clock last-write-wins is unsafe: clock skew, malicious clients, ties, and out-of-order delivery can silently lose edits.

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

    Grok 4.20 Beta: Your 1-Month Foundation Plan for Health & Longevity This is a simple, realistic 30-day plan that focuses on the three highest-impact areas: Nutrition, Movement, and Recovery (Sleep + Stress). The goal is to build consistent daily habits rather than perfection.

    Nex-N2.5-Pro (free): 1-Month Beginner Health & Longevity Plan Goal: Build simple habits you can keep—not perfection. Focus on 3 areas: diet, exercise, and sleep/stress. Diet: Eat for steady energy Week 1: Add before you subtract Add 1 fruit or vegetable to 2 meals per day. Drink a glass of water when you wake up and before meals.

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

    Grok 4.20 Beta: The 3 weakest claims are: Vision / Core Claim: "reads your brainwaves to predict what you want to type before you think it" (Slide 1) and "decode neural patterns into text with 94% accuracy" (Slide 3) Why it's weak: This is the single most important claim in the entire deck, and it is extraordinarily implausible with…

    Nex-N2.5-Pro (free): The 3 weakest claims are the ones most likely to be challenged in diligence: Weakest claim Why it’s weak How to strengthen it 1. “94% accuracy… works with any language, any device.” This is the biggest scientific and product credibility risk.

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

    Grok 4.20 Beta: Here are all the clauses that are heavily one-sided and exploitable against the Contractor, along with specific red-line modifications and the legal/business reasoning behind each.

    Nex-N2.5-Pro (free): Below is a general contract-risk review, not legal advice. Enforceability depends heavily on jurisdiction, contractor classification, and the exact facts. Also, even if a clause might be unenforceable, relying on that is risky because litigation/arbitration is expensive.

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

    Grok 4.20 Beta: 1. For the experienced software engineer Think of an LLM as a massive probabilistic state machine that was trained to compress internet-scale text into a ridiculously efficient next-token prediction function. You don't hand-code any rules.

    Nex-N2.5-Pro (free): To the experienced software engineer Think of an LLM as a giant probabilistic text service trained by repeatedly asking: “Given this sequence of tokens so far, what is the next token?”

    Every model's answer to this prompt

Favorites

Movie

Album

Book

City

Same pick

Game

Grok 4.20 BetaGrok 4.20 Beta

The Matrix

1999

The Dark Side of the Moon

Pink Floyd

The Hitchhiker's Guide to the Galaxy

Douglas Adams

Tokyo

Japan

The Legend of Zelda: Ocarina of Time

Action

Nex-N2.5-Pro (free)Nex-N2.5-Pro (free)

Blade Runner 2049

2017

Kind of Blue

Miles Davis

Мастер и Маргарита

Михаил Афанасьевич Булгаков

Tokyo

Japan

The Legend of Zelda: Breath of the Wild

Adventure, Action

Price and specs

Not enough votes to call it. On the specs, Grok 4.20 Beta has the edge: bigger model tier, bigger context window, major provider backing.

Grok 4.20 Beta and Nex-N2.5-Pro (free) compared across 14 shared prompts
SpecGrok 4.20 BetaNex-N2.5-Pro (free)
Input price$2/M tokensFree
Output price$6/M tokensFree
Context window2.0M tokens262K tokens
WeightsClosed—
Free API (OpenRouter)NoNo
ReleasedMar 2026Sep 2026
At 10M a month$20.00$20.00$0$0
1M10M100M1B10M tokens

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

Where to run it1 host
Grok 4.20 Beta1 host
HostInOutContextUptime
  • xAI$1.25 in·$2.50 out·2M·90.3% up
Nex-N2.5-Pro (free)

No hosts listed on OpenRouter.

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

Common questions

What is the difference between Grok 4.20 Beta and Nex-N2.5-Pro (free)?

Grok 4.20 Beta is developed by xAI while Nex-N2.5-Pro (free) is developed by Nex AGI. Grok 4.20 Beta has a 2.0M token context window vs Nex-N2.5-Pro (free)'s 262K. You can compare their actual outputs across 14 challenges on Rival to see how they differ in practice.

Which is better, Grok 4.20 Beta or Nex-N2.5-Pro (free)?

It depends on your use case. Grok 4.20 Beta and Nex-N2.5-Pro (free) 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.

How much does Grok 4.20 Beta cost compared to Nex-N2.5-Pro (free)?

Grok 4.20 Beta costs $2/M input tokens and Nex-N2.5-Pro (free) costs $0/M input tokens. Nex-N2.5-Pro (free) is $2.00/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 Grok 4.20 Beta and Nex-N2.5-Pro (free) on Rival?

This page shows a side-by-side comparison of Grok 4.20 Beta and Nex-N2.5-Pro (free) 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.

More comparisons

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  • Grok 4.20 Beta vs GPT-6.1 SolLanded Sep 2026
  • Nex-N2.5-Pro (free) vs Claude Sonnet 5.5Landed Sep 2026
  • Grok 4.20 Beta vs Solar Mini 4Landed Sep 2026
  • Nex-N2.5-Pro (free) vs Qwen3.8 Max PrimeLanded Sep 2026

Same lab, same size, long tail

  • Grok 4.20 Beta vs Grok 4.20 Multi-Agent BetaVersion compare
  • Grok 4.20 Beta vs Grok 4.7Same lab
  • Nex-N2.5-Pro (free) vs Nex-N2.5-Mini (free)Same lab
  • Nex-N2.5-Pro (free) vs Ox AlphaSame size
  • Nex-N2.5-Pro (free) vs Mistral Small CreativeNew provider
  • Grok 4.20 Beta vs Muse Glimmer 30BNew provider
  • Nex-N2.5-Pro (free) vs Muse Spark 1.1Same size
  • Nex-N2.5-Pro (free) vs Muse Spark 1.3Same size

Model pages

  • Grok 4.20 Beta53 outputs, specs and price
  • Nex-N2.5-Pro (free)14 outputs, specs and price
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