AI Model Release Tracker - Timeline of Major AI Models from 2022-2026

Home/Compare/Claude Opus 4.1 vs Grok 4 Fast

Claude Opus 4.1 vs Grok 4 Fast

2 vs 0 benchmarks won

Anthropic
Claude Opus 4.1
xAI
Grok 4 Fast
Overview
CompanyAnthropicxAI
Release dateAug 5 2025Sep 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Science reasoning
GPQA Diamond
80.9%
Software engineering
SWE-Bench Verified
74.5%
Multimodal understanding
MMMU
Timeline
Release gapClaude Opus 4.1 shipped 27 days before Grok 4 Fast

Which is better: Claude Opus 4.1 or Grok 4 Fast?

Claude Opus 4.1 leads Grok 4 Fast on 2 of the tracked benchmarks (GPQA Diamond, SWE-Bench Verified, MMMU). Claude Opus 4.1 shipped 27 days before Grok 4 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 Opus 4.1 released?
Claude Opus 4.1 was released by Anthropic on Aug 5 2025.
When was Grok 4 Fast released?
Grok 4 Fast was released by xAI on Sep 2025.

Other comparisons