Noometry

Model comparison

Claude 3 Opus vs Grok 4 Fast

Grok 4 Fast is the stronger model overall, scoring 39.4 to 29.5 on the Noometry Index.

Last verified . 22 shared benchmarks.

Claude 3 Opus Anthropic

29.5

Rank #310 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 22 benchmarks with published results for both. Claude 3 Opus scores higher in 1 category and Grok 4 Fast in 8 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 38.2.
  • The biggest single-benchmark swing is WeirdML: 19.2% for Claude 3 Opus and 42.9% for Grok 4 Fast.

Side by side

Claude 3 OpusGrok 4 Fast
ProviderAnthropicxAI
Noometry Index29.539.4
Released2024-02-292025-09-19
WeightsProprietaryProprietary
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked4630

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Category by category

Coding Too close to call

Claude 3 Opus: 32.9 (#267), Grok 4 Fast: 32.5 (#271)

BenchmarkClaude 3 OpusGrok 4 Fast
WeirdML19.2%42.9%
LMArena Coding12641429
LMArena WebDev—1159
BigCodeBench Instruct45.5%—
LiveBench Coding38.6%—
BigCodeBench Complete57.4%—
HumanEval+77.4%—
MBPP+73.3%—

Agentic & Tool Use Grok 4 Fast leads

Claude 3 Opus: 24.6 (#116), Grok 4 Fast: 29.5 (#86)

BenchmarkClaude 3 OpusGrok 4 Fast
Cybench10%30%
τ²-bench Banking—15.7%
LMArena Search—1171
METR Time Horizons29.5%—

Reasoning Grok 4 Fast leads

Claude 3 Opus: 14.6 (#324), Grok 4 Fast: 22.2 (#201)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Hard Prompts12451412
DTBench61.6%82.7%
Epoch Capabilities Index126.91144.2
ForecastBench58.460.5
ARC-AGI-2—5.3%
SimpleBench23.5%—
Kagi LLM Benchmark—66.1%
ARC-AGI-1—48.5%
Chess Puzzles5%—
EnigmaEval0.8%—
LiveBench Reasoning40.6%—
LiveBench Data Analysis57.9%—
LMCA17%—
LiveBench49.2%—
WinoGrande88.5%—

Math Grok 4 Fast leads

Claude 3 Opus: 14.8 (#299), Grok 4 Fast: 38.9 (#123)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Math12731419
OTIS Mock AIME 2024-20254.7%—
LiveBench Math43.6%—
MATH Level 537.5%—

Knowledge Grok 4 Fast leads

Claude 3 Opus: 24.5 (#267), Grok 4 Fast: 32.0 (#214)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Expert12231411
GPQA Diamond47.2%—
SimpleQA Verified12.6%—
Confabulations22.7%—
Vectara Hallucination Rate—19.7%
MMLU84.6%—

Multimodal Not comparable

Claude 3 Opus: 27.1 (#116), Grok 4 Fast: —

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Vision1023—

Multilingual Grok 4 Fast leads

Claude 3 Opus: 41.4 (#207), Grok 4 Fast: 51.3 (#111)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Non-English12581396
LMArena Chinese12481457
LMArena French12751431
LMArena German12581383
LMArena Japanese12041352
LMArena Korean11871357
LMArena Russian12801389
LMArena Spanish12461415

Instruction Following Grok 4 Fast leads

Claude 3 Opus: 64.1 (#228), Grok 4 Fast: 73.2 (#121)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Instruction Following12481387
LiveBench Instruction Following63.9%—

Long Context Grok 4 Fast leads

Claude 3 Opus: 38.2 (#202), Grok 4 Fast: 63.2 (#3)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Longer Query12591415
Fiction.LiveBench—94.4%

Writing & Preference Grok 4 Fast leads

Claude 3 Opus: 47.2 (#213), Grok 4 Fast: 60.0 (#102)

BenchmarkClaude 3 OpusGrok 4 Fast
LMArena Text12621407
LMArena Creative Writing12351387
LMArena Multi-Turn12751414
LiveBench Language50.4%—

Frequently asked questions

Is Claude 3 Opus better than Grok 4 Fast?

Grok 4 Fast is the stronger model overall, scoring 39.4 to 29.5 on the Noometry Index.

Is Claude 3 Opus or Grok 4 Fast better for coding?

They score almost the same on coding (32.9 vs 32.5); test both on your own repository before choosing.

How many benchmarks do Claude 3 Opus and Grok 4 Fast share?

22 benchmarks have published results for both models. Claude 3 Opus has 46 scored results on Noometry and Grok 4 Fast has 30.

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