Noometry

Model comparison

Grok 4 Fast vs Qwen3.5-Flash

Qwen3.5-Flash is the stronger model overall, scoring 42.5 to 39.4 on the Noometry Index.

Last verified . 21 shared benchmarks.

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Qwen3.5-Flash Alibaba (Qwen)

42.5

Rank #112 Confirmed

Summary

  • They share 21 benchmarks with published results for both. Grok 4 Fast scores higher in 5 categories and Qwen3.5-Flash in 3 categories; 6 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 42.4.
  • The biggest single-benchmark swing is Vectara Hallucination Rate: 19.7% for Grok 4 Fast and 10.5% for Qwen3.5-Flash.

Side by side

Grok 4 FastQwen3.5-Flash
ProviderxAIAlibaba (Qwen)
Noometry Index39.442.5
Released2025-09-192026-02-23
WeightsProprietaryProprietary
Context window—1M
Max output—66K
Input $ / M tokens—$0.10
Output $ / M tokens—$0.40
Results tracked3032

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Category by category

Coding Qwen3.5-Flash leads

Grok 4 Fast: 32.5 (#271), Qwen3.5-Flash: 34.2 (#242)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena WebDev11591244
LMArena Coding14291412
WeirdML42.9%—
ALE-Bench—221.8

Agentic & Tool Use Not comparable

Grok 4 Fast: 29.5 (#86), Qwen3.5-Flash: —

BenchmarkGrok 4 FastQwen3.5-Flash
τ²-bench Banking15.7%—
Cybench30%—
LMArena Search1171—
Vending-Bench 2—462.69

Reasoning Qwen3.5-Flash leads

Grok 4 Fast: 22.2 (#201), Qwen3.5-Flash: 33.7 (#72)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena Hard Prompts14121403
DTBench82.7%82.9%
Epoch Capabilities Index144.2143.98
ARC-AGI-25.3%—
Kagi LLM Benchmark66.1%—
ARC-AGI-148.5%—
Chess Puzzles—21%
Mystery Game Puzzles—20%
LMCA—29.1%
ForecastBench60.5—

Math Grok 4 Fast leads

Grok 4 Fast: 38.9 (#123), Qwen3.5-Flash: 37.4 (#158)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena Math14191407
FrontierMath (Tiers 1-3)—18.2%
OTIS Mock AIME 2024-2025—84.4%
FrontierMath (Feb 2025 set)—6.2%
FrontierMath Tier 4 (v1)—0%

Knowledge Qwen3.5-Flash leads

Grok 4 Fast: 32.0 (#214), Qwen3.5-Flash: 43.2 (#93)

BenchmarkGrok 4 FastQwen3.5-Flash
Vectara Hallucination Rate19.7%10.5%
LMArena Expert14111407
GPQA Diamond—82.3%
SimpleQA Verified—20.3%

Multilingual Too close to call

Grok 4 Fast: 51.3 (#111), Qwen3.5-Flash: 50.5 (#121)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena Non-English13961385
LMArena Chinese14571446
LMArena French14311412
LMArena German13831390
LMArena Japanese13521368
LMArena Korean13571344
LMArena Russian13891379
LMArena Spanish14151400

Instruction Following Too close to call

Grok 4 Fast: 73.2 (#121), Qwen3.5-Flash: 72.6 (#139)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena Instruction Following13871374

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), Qwen3.5-Flash: 42.4 (#124)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena Longer Query14151392
Fiction.LiveBench94.4%—

Writing & Preference Grok 4 Fast leads

Grok 4 Fast: 60.0 (#102), Qwen3.5-Flash: 57.9 (#122)

BenchmarkGrok 4 FastQwen3.5-Flash
LMArena Text14071397
LMArena Creative Writing13871343
LMArena Multi-Turn14141393

Frequently asked questions

Is Grok 4 Fast better than Qwen3.5-Flash?

Qwen3.5-Flash is the stronger model overall, scoring 42.5 to 39.4 on the Noometry Index.

Is Grok 4 Fast or Qwen3.5-Flash better for coding?

Qwen3.5-Flash scores higher on coding benchmarks: 34.2 versus 32.5 in the Noometry coding category.

How many benchmarks do Grok 4 Fast and Qwen3.5-Flash share?

21 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Qwen3.5-Flash has 32.

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