> Claude Fable 5.1 vs Gemini 4 Argon: index scores 192 and ~188 (GPT-4 = 100), API prices, context windows and results on the same independent tests, side by side.

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# Compare

Side by side on the same independent tests, with price and context. The link in your address bar shares this exact comparison.

[Claude Fable 5.1](https://themodelindex.org/models/claude-fable-5-1/)

[Gemini 4 Argon](https://themodelindex.org/models/gemini-4-argon/)

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Next to Claude Fable 5.1

Cheapest at this level

Claude Sonnet 5.5

Best open model, measured

Kimi K3

Stronger for the same price

Claude Opus 5.5

The version it replaced

Claude Fable 5

Where it started

GPT-4

Presets

Best open vs best closed (measured)

Today vs GPT-4 (2023)

Top three labs

US vs China, best of each

[Claude Fable 5.1](https://themodelindex.org/models/claude-fable-5-1/)

192

181–203

Weights

Closed

Released

Sep 2026

Price in / out

$10 / $50

Context

1M

Core tests taken

4 of 8

[Gemini 4 Argon](https://themodelindex.org/models/gemini-4-argon/)

~188

estimated

Weights

Closed

Released

Sep 2026

Price in / out

–

Context

–

Core tests taken

–

Claude Fable 5.1 and Gemini 4 Argon are too close to call (5 points apart, within the uncertainty) (one score is an estimate).

## Test by test · independent results · Epoch AI

Claude Fable 5.1

Gemini 4 Argon

These models share no independent tests yet.

Only tests that at least two of these models have taken. Bold rows are the core tests shown on every profile; all of these results inform the index score. Task length (METR) is listed below the chart because it is a duration, not a percentage.

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Source: https://themodelindex.org/compare/claude-fable-5-1-vs-gemini-4-argon/ · The Model Index · data as of 2026-10-01