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Claude 3.5 Sonnet vs Grok 4.1 Fast

2 vs 0 benchmarks won

Anthropic
Claude 3.5 Sonnet
xAI
Grok 4.1 Fast
Overview
CompanyAnthropicxAI
Release dateJun 20 2024Nov 19 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
59.4%
Software engineering
SWE-Bench Verified
33.4%
Multimodal understanding
MMMU
Timeline
Release gapClaude 3.5 Sonnet shipped 517 days before Grok 4.1 Fast

Which is better: Claude 3.5 Sonnet or Grok 4.1 Fast?

Claude 3.5 Sonnet leads Grok 4.1 Fast on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude 3.5 Sonnet shipped 517 days before Grok 4.1 Fast, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

Direct benchmark comparisons are unavailable — at least one of these models has not published scores on GPQA Diamond, SWE-Bench Verified, or MMMU.

Frequently asked questions

When was Claude 3.5 Sonnet released?
Claude 3.5 Sonnet was released by Anthropic on Jun 20 2024.
When was Grok 4.1 Fast released?
Grok 4.1 Fast was released by xAI on Nov 19 2025.

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