Noometry

Model comparison

Claude Opus 4.6 vs Grok 4 Fast

Claude Opus 4.6 is the stronger model overall, scoring 58.2 to 39.4 on the Noometry Index.

Last verified . 29 shared benchmarks.

Claude Opus 4.6 Anthropic

58.2

Rank #20 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 29 benchmarks with published results for both. Claude Opus 4.6 scores higher in 8 categories and Grok 4 Fast in 1 category; 9 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Claude Opus 4.6 leads 57.8 to 22.2.
  • The biggest single-benchmark swing is ARC-AGI-2: 69.2% for Claude Opus 4.6 and 5.3% for Grok 4 Fast.

Side by side

Claude Opus 4.6Grok 4 Fast
ProviderAnthropicxAI
Noometry Index58.239.4
Released2026-02-042025-09-19
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$5—
Output $ / M tokens$25—
Results tracked6830

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Category by category

Coding Claude Opus 4.6 leads

Claude Opus 4.6: 57.2 (#20), Grok 4 Fast: 32.5 (#271)

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena WebDev15471159
WeirdML78%42.9%
LMArena Coding15361429
SWE-bench Verified78.7%—
FrontierCode26.6%—
SWE-bench Verified (bash only)75.6%—
SWE-bench Multilingual72%—
GSO41.2%—
ALE-Bench996.5—
AlgoTune1.47—

Agentic & Tool Use Claude Opus 4.6 leads

Claude Opus 4.6: 51.1 (#4), Grok 4 Fast: 29.5 (#86)

BenchmarkClaude Opus 4.6Grok 4 Fast
τ²-bench Banking27.3%15.7%
Cybench93%30%
LMArena Search12531171
Terminal-Bench79.8%—
APEX-Agents46.3%—
Remote Labor Index4.2%—
DeepResearch Bench55.3%—
GBAEval44.1%—
METR Time Horizons78.9%—
Vending-Bench 28,018—

Reasoning Claude Opus 4.6 leads

Claude Opus 4.6: 57.8 (#23), Grok 4 Fast: 22.2 (#201)

BenchmarkClaude Opus 4.6Grok 4 Fast
ARC-AGI-269.2%5.3%
Kagi LLM Benchmark83.6%66.1%
ARC-AGI-194%48.5%
LMArena Hard Prompts15271412
DTBench91.2%82.7%
Epoch Capabilities Index155.24144.2
ForecastBench6060.5
SimpleBench67.6%—
NYT Connections (extended)92.1%—
Chess Puzzles17%—
EnigmaEval7.6%—
Thematic Generalization80.6%—
EBR-Bench12.7%—
Mystery Game Puzzles25%—
LMCA55.8%—

Math Claude Opus 4.6 leads

Claude Opus 4.6: 63.0 (#31), Grok 4 Fast: 38.9 (#123)

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena Math15191419
FrontierMath (Tiers 1-3)66%—
FrontierMath Tier 426.8%—
MathArena Final-Answer Competitions78.5%—
OTIS Mock AIME 2024-202594.4%—
ProofBench50%—
FrontierMath (Feb 2025 set)40.7%—
FrontierMath Tier 4 (v1)22.9%—

Knowledge Claude Opus 4.6 leads

Claude Opus 4.6: 61.9 (#26), Grok 4 Fast: 32.0 (#214)

BenchmarkClaude Opus 4.6Grok 4 Fast
Vectara Hallucination Rate12.2%19.7%
LMArena Expert15461411
GPQA Diamond90.5%—
Humanity's Last Exam34.4%—
SimpleQA Verified47%—

Multimodal Not comparable

Claude Opus 4.6: 37.3 (#74), Grok 4 Fast: —

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena Vision1316—
Furniture Assembly28.3%—
LMArena Document1507—

Multilingual Claude Opus 4.6 leads

Claude Opus 4.6: 57.9 (#6), Grok 4 Fast: 51.3 (#111)

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena Non-English14891396
LMArena Chinese15511457
LMArena French15131431
LMArena German15021383
LMArena Japanese14841352
LMArena Korean14641357
LMArena Russian14971389
LMArena Spanish15101415

Instruction Following Claude Opus 4.6 leads

Claude Opus 4.6: 79.5 (#4), Grok 4 Fast: 73.2 (#121)

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena Instruction Following15231387

Long Context Grok 4 Fast leads

Claude Opus 4.6: 48.1 (#13), Grok 4 Fast: 63.2 (#3)

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena Longer Query15201415
Fiction.LiveBench—94.4%
CL-bench20.7%—
CL-bench Life17%—

Writing & Preference Claude Opus 4.6 leads

Claude Opus 4.6: 73.5 (#10), Grok 4 Fast: 60.0 (#102)

BenchmarkClaude Opus 4.6Grok 4 Fast
LMArena Text15031407
LMArena Creative Writing15051387
LMArena Multi-Turn15131414
EQ-Bench Creative Writing1809—
EQ-Bench 41223—

Frequently asked questions

Is Claude Opus 4.6 better than Grok 4 Fast?

Claude Opus 4.6 is the stronger model overall, scoring 58.2 to 39.4 on the Noometry Index.

Is Claude Opus 4.6 or Grok 4 Fast better for coding?

Claude Opus 4.6 scores higher on coding benchmarks: 57.2 versus 32.5 in the Noometry coding category.

How many benchmarks do Claude Opus 4.6 and Grok 4 Fast share?

29 benchmarks have published results for both models. Claude Opus 4.6 has 68 scored results on Noometry and Grok 4 Fast has 30.

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