Noometry

Model comparison

Claude Opus 4 vs Grok 4 Fast

Claude Opus 4 is the stronger model overall, scoring 43.1 to 39.4 on the Noometry Index.

Last verified . 28 shared benchmarks.

Claude Opus 4 Anthropic

43.1

Rank #100 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 28 benchmarks with published results for both. Claude Opus 4 scores higher in 7 categories and Grok 4 Fast in 2 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 39.6.
  • The biggest single-benchmark swing is Fiction.LiveBench: 61.1% for Claude Opus 4 and 94.4% for Grok 4 Fast.

Side by side

Claude Opus 4Grok 4 Fast
ProviderAnthropicxAI
Noometry Index43.139.4
Released2025-05-222025-09-19
WeightsProprietaryProprietary
Context window200K—
Max output32K—
Input $ / M tokens$15—
Output $ / M tokens$75—
Results tracked5630

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Category by category

Coding Claude Opus 4 leads

Claude Opus 4: 47.2 (#62), Grok 4 Fast: 32.5 (#271)

BenchmarkClaude Opus 4Grok 4 Fast
WeirdML43.7%42.9%
LMArena Coding14421429
SWE-bench Verified70.7%—
SWE-bench Verified (bash only)67.6%—
Aider Polyglot72%—
LMArena WebDev—1159
GSO6.9%—
AlgoTune1.33—

Agentic & Tool Use Claude Opus 4 leads

Claude Opus 4: 34.8 (#42), Grok 4 Fast: 29.5 (#86)

BenchmarkClaude Opus 4Grok 4 Fast
Cybench38%30%
LMArena Search11271171
τ²-bench Banking—15.7%
DeepResearch Bench46.8%—
METR Time Horizons63.9%—

Reasoning Claude Opus 4 leads

Claude Opus 4: 27.3 (#121), Grok 4 Fast: 22.2 (#201)

BenchmarkClaude Opus 4Grok 4 Fast
ARC-AGI-28.6%5.3%
Kagi LLM Benchmark74.3%66.1%
ARC-AGI-135.7%48.5%
LMArena Hard Prompts13991412
DTBench81.6%82.7%
Epoch Capabilities Index142.67144.2
ForecastBench61.160.5
SimpleBench58.8%—
CritPt0.3%—
EnigmaEval5.6%—
LMCA37.4%—

Math Claude Opus 4 leads

Claude Opus 4: 42.0 (#86), Grok 4 Fast: 38.9 (#123)

BenchmarkClaude Opus 4Grok 4 Fast
LMArena Math13901419
OTIS Mock AIME 2024-202564.4%—
Omni-MATH61.6%—
MATH Level 585%—
FrontierMath (Feb 2025 set)4.5%—
FrontierMath Tier 4 (v1)4.2%—

Knowledge Claude Opus 4 leads

Claude Opus 4: 44.0 (#88), Grok 4 Fast: 32.0 (#214)

BenchmarkClaude Opus 4Grok 4 Fast
Vectara Hallucination Rate12%19.7%
LMArena Expert13861411
GPQA Diamond76.3%—
Humanity's Last Exam10.7%—
MMLU-Pro87.5%—
Confabulations15.9%—
GPQA (HELM)70.8%—

Multimodal Not comparable

Claude Opus 4: 31.5 (#106), Grok 4 Fast: —

BenchmarkClaude Opus 4Grok 4 Fast
LMArena Vision1192—
GeoBench49%—
VPCT38%—

Multilingual Grok 4 Fast leads

Claude Opus 4: 48.8 (#138), Grok 4 Fast: 51.3 (#111)

BenchmarkClaude Opus 4Grok 4 Fast
LMArena Non-English13621396
LMArena Chinese13861457
LMArena French13721431
LMArena German13911383
LMArena Japanese13311352
LMArena Korean13211357
LMArena Russian13921389
LMArena Spanish13891415

Instruction Following Claude Opus 4 leads

Claude Opus 4: 77.1 (#28), Grok 4 Fast: 73.2 (#121)

BenchmarkClaude Opus 4Grok 4 Fast
LMArena Instruction Following14061387
IFEval91.8%—

Long Context Grok 4 Fast leads

Claude Opus 4: 39.6 (#172), Grok 4 Fast: 63.2 (#3)

BenchmarkClaude Opus 4Grok 4 Fast
Fiction.LiveBench61.1%94.4%
LMArena Longer Query14221415

Writing & Preference Claude Opus 4 leads

Claude Opus 4: 61.2 (#89), Grok 4 Fast: 60.0 (#102)

BenchmarkClaude Opus 4Grok 4 Fast
LMArena Text13771407
LMArena Creative Writing13871387
LMArena Multi-Turn13961414
Short-Story Creative Writing83.6%—
EQ-Bench Creative Writing1580—
WildBench85.2%—

Frequently asked questions

Is Claude Opus 4 better than Grok 4 Fast?

Claude Opus 4 is the stronger model overall, scoring 43.1 to 39.4 on the Noometry Index.

Is Claude Opus 4 or Grok 4 Fast better for coding?

Claude Opus 4 scores higher on coding benchmarks: 47.2 versus 32.5 in the Noometry coding category.

How many benchmarks do Claude Opus 4 and Grok 4 Fast share?

28 benchmarks have published results for both models. Claude Opus 4 has 56 scored results on Noometry and Grok 4 Fast has 30.

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