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Gemini 3.5 Flash vs Grok 4 Fast

Google Gemini 3.5 Flash vs xAI Grok 4 Fast — side-by-side specs.

Google
Gemini 3.5 Flash
xAI
Grok 4 Fast
Overview
CompanyGooglexAI
Release dateMay 19 2026Sep 2025
Model type
Open sourceNoNo
Specifications
Parameters
Context window
Benchmarks
Agentic coding
SWE-Bench Pro
55.1%
Agentic terminal coding
Terminal-Bench 2.1
76.2%
Multi-step tool use
MCP Atlas
83.6%
General tool use
Toolathlon
56.5%
Multidisciplinary reasoning
Humanity's Last Exam · no tools
40.2%
Abstract reasoning
ARC-AGI-2
72.1%
Agentic computer use
OSWorld-Verified
78.4%
Agentic financial analysis
Finance Agent v2
57.9%
Knowledge work
GDPval-AA
1656
Chart reasoning
CharXiv Reasoning
84.2%
Multimodal reasoning
MMMU-Pro
83.6%
Spatial reasoning
Blueprint-Bench 2
33.6%
Long context
MRCR v2 (8-needle) · 128k average
77.3%
Long context
MRCR v2 (8-needle) · 1M pointwise
26.6%
Timeline
Release gapGrok 4 Fast shipped 260 days before Gemini 3.5 Flash

Which is better: Gemini 3.5 Flash or Grok 4 Fast?

Gemini 3.5 Flash and Grok 4 Fast don't publish scores on any of the same benchmarks, so there's no direct head-to-head comparison. Grok 4 Fast shipped 260 days before Gemini 3.5 Flash, 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 — Gemini 3.5 Flash and Grok 4 Fast don't publish scores on any of the same benchmarks.

Frequently asked questions

When was Gemini 3.5 Flash released?
Gemini 3.5 Flash was released by Google on May 19 2026.
When was Grok 4 Fast released?
Grok 4 Fast was released by xAI on Sep 2025.

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