Noometry

Model comparison

Claude Opus 4.1 vs Grok 4 Fast

Claude Opus 4.1 is the stronger model overall, scoring 40.8 to 39.0 on the Noometry Index.

Last verified . 25 shared benchmarks.

Claude Opus 4.1 Anthropic

40.8

Rank #136 Confirmed

Grok 4 Fast xAI

39.0

Rank #164 Confirmed

Summary

  • They share 25 benchmarks with published results for both. Claude Opus 4.1 scores higher in 7 categories and Grok 4 Fast in 2 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 44.5.
  • The biggest single-benchmark swing is Cybench: 42% for Claude Opus 4.1 and 30% for Grok 4 Fast.

Side by side

Claude Opus 4.1Grok 4 Fast
ProviderAnthropicxAI
Noometry Index40.839.0
Released2025-08-052025-09-19
WeightsProprietaryProprietary
Context window200K—
Max output32K—
Input $ / M tokens$15—
Output $ / M tokens$75—
Results tracked4830

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Category by category

Coding Claude Opus 4.1 leads

Claude Opus 4.1: 44.3 (#69), Grok 4 Fast: 32.3 (#264)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena WebDev13901160
WeirdML45.9%42.9%
LMArena Coding14791429
SWE-bench Verified73.3%—
ALE-Bench674.77—
AlgoTune1.34—

Agentic & Tool Use Claude Opus 4.1 leads

Claude Opus 4.1: 34.8 (#38), Grok 4 Fast: 29.3 (#80)

BenchmarkClaude Opus 4.1Grok 4 Fast
Cybench42%30%
LMArena Search11481171
Terminal-Bench38%—
GDPval43.6%—
τ²-bench Banking—15.7%
DeepResearch Bench48.3%—
METR Time Horizons66.8%—

Reasoning Claude Opus 4.1 leads

Claude Opus 4.1: 31.6 (#70), Grok 4 Fast: 22.5 (#179)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena Hard Prompts14431413
DTBench80%82.7%
Epoch Capabilities Index144.11144.21
ForecastBench6260.5
ARC-AGI-2—5.3%
SimpleBench60%—
Kagi LLM Benchmark—66.1%
ARC-AGI-1—48.5%
Chess Puzzles7%—
EnigmaEval7.2%—
EBR-Bench7.9%—
Mystery Game Puzzles21%—
LMCA37.1%—

Math Grok 4 Fast leads

Claude Opus 4.1: 22.0 (#267), Grok 4 Fast: 36.1 (#126)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena Math14301419
FrontierMath (Tiers 1-3)12.6%—
FrontierMath Tier 42.4%—
OTIS Mock AIME 2024-202568.9%—
FrontierMath (Feb 2025 set)7.2%—
FrontierMath Tier 4 (v1)4.2%—

Knowledge Claude Opus 4.1 leads

Claude Opus 4.1: 41.9 (#93), Grok 4 Fast: 31.5 (#211)

BenchmarkClaude Opus 4.1Grok 4 Fast
Vectara Hallucination Rate11.8%19.7%
LMArena Expert14391411
GPQA Diamond77.3%—
Humanity's Last Exam11.5%—
Confabulations17.1%—

Multimodal Not comparable

Claude Opus 4.1: 26.2 (#114), Grok 4 Fast: —

BenchmarkClaude Opus 4.1Grok 4 Fast
VPCT35%—

Multilingual Too close to call

Claude Opus 4.1: 52.1 (#90), Grok 4 Fast: 51.5 (#106)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena Non-English14051397
LMArena Chinese14271458
LMArena French14321433
LMArena German14121383
LMArena Japanese13781358
LMArena Korean13811359
LMArena Russian14211387
LMArena Spanish14481414

Instruction Following Claude Opus 4.1 leads

Claude Opus 4.1: 75.8 (#53), Grok 4 Fast: 73.4 (#116)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena Instruction Following14361388

Long Context Grok 4 Fast leads

Claude Opus 4.1: 44.5 (#60), Grok 4 Fast: 63.2 (#3)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena Longer Query14551415
Fiction.LiveBench—94.4%

Writing & Preference Claude Opus 4.1 leads

Claude Opus 4.1: 62.6 (#70), Grok 4 Fast: 60.2 (#96)

BenchmarkClaude Opus 4.1Grok 4 Fast
LMArena Text14191407
LMArena Creative Writing14121388
LMArena Multi-Turn14441414
Short-Story Creative Writing84.7%—

Frequently asked questions

Is Claude Opus 4.1 better than Grok 4 Fast?

Claude Opus 4.1 is the stronger model overall, scoring 40.8 to 39.0 on the Noometry Index.

Is Claude Opus 4.1 or Grok 4 Fast better for coding?

Claude Opus 4.1 scores higher on coding benchmarks: 44.3 versus 32.3 in the Noometry coding category.

How many benchmarks do Claude Opus 4.1 and Grok 4 Fast share?

25 benchmarks have published results for both models. Claude Opus 4.1 has 48 scored results on Noometry and Grok 4 Fast has 30.

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