Model comparison

Claude Fable 5.1 vs Grok 4

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 48.1 on the Noometry Index.

Last verified . 24 shared benchmarks.

Claude Fable 5.1 Anthropic

69.0

Rank #2 Confirmed

Grok 4 xAI

48.1

Rank #56 Confirmed

Summary

  • They share 24 benchmarks with published results for both. Claude Fable 5.1 scores higher in 8 categories and Grok 4 in 2 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in math, where Claude Fable 5.1 leads 89.6 to 48.4.
  • The biggest single-benchmark swing is ARC-AGI-2: 90% for Claude Fable 5.1 and 16% for Grok 4.

Side by side

Claude Fable 5.1 and Grok 4 specifications
Claude Fable 5.1Grok 4
ProviderAnthropicxAI
Noometry Index69.048.1
Released2026-09-012025-07-09
WeightsProprietaryProprietary
Context window1M—
Max output128K—
Input $ / M tokens$10—
Output $ / M tokens$50—
Results tracked5248

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 74.7 (#1), Grok 4: 50.3 (#46)

Coding benchmarks
BenchmarkClaude Fable 5.1Grok 4
WeirdML92.9%45.7%
LMArena Coding15281408
FrontierCode50.9%—
Aider Polyglot—79.6%
CursorBench51.8%—
LMArena WebDev1744—
FrontierSWE56.3%—
SciCode63.1%—
GSO88.2%—
MirrorCode73.3%—
ALE-Bench2,143—

Agentic & Tool Use Claude Fable 5.1 leads

Claude Fable 5.1: 50.7 (#5), Grok 4: 32.3 (#68)

Agentic & Tool Use benchmarks
BenchmarkClaude Fable 5.1Grok 4
Terminal-Bench—27.2%
APEX-Agents68.6%—
Berkeley Function Calling Leaderboard—63%
GDPval—21.1%
Remote Labor Index17.9%—
Cybench—43%
DeepResearch Bench—47.3%
BALROG—43.6%
GDP.pdf29.6%—
LMArena Search—1142
METR Time Horizons—66.6%
Vending-Bench 25,422—

Reasoning Claude Fable 5.1 leads

Claude Fable 5.1: 76.7 (#7), Grok 4: 36.7 (#65)

Reasoning benchmarks
BenchmarkClaude Fable 5.1Grok 4
ARC-AGI-290%16%
ARC-AGI-197.5%66.7%
Chess Puzzles47%28%
LMArena Hard Prompts15261409
Epoch Capabilities Index164.7146.44
SimpleBench—60.5%
Kagi LLM Benchmark—73.6%
NYT Connections (extended)90%—
CritPt31.1%—
EBR-Bench57.1%—
Mystery Game Puzzles58%—
DTBench97.6%—
LMCA65.5%—
ForecastBench—60.9

Math Claude Fable 5.1 leads

Claude Fable 5.1: 89.6 (#4), Grok 4: 48.4 (#64)

Math benchmarks
BenchmarkClaude Fable 5.1Grok 4
OTIS Mock AIME 2024-2025100%84%
LMArena Math15251422
FrontierMath (Tiers 1-3)90.2%—
FrontierMath Tier 487.8%—
ProofBench100%—
Omni-MATH—60.3%
FrontierMath (Feb 2025 set)—19.7%
FrontierMath Erdős0%—
FrontierMath Tier 4 (v1)—2.1%

Knowledge Claude Fable 5.1 leads

Claude Fable 5.1: 69.6 (#6), Grok 4: 53.8 (#55)

Knowledge benchmarks
BenchmarkClaude Fable 5.1Grok 4
LMArena Expert15351415
GPQA Diamond—87%
Humanity's Last Exam46.5%—
SimpleQA Verified70.8%—
MMLU-Pro—85.1%
Confabulations—12.4%
GPQA (HELM)—72.7%

Multimodal Claude Fable 5.1 leads

Claude Fable 5.1: 53.9 (#4), Grok 4: 33.7 (#94)

Multimodal benchmarks
BenchmarkClaude Fable 5.1Grok 4
LMArena Vision13181210
GeoBench—45%
Blueprint-Bench 241.9%—
Furniture Assembly70%—
LMArena Document1513—

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.1 (#3), Grok 4: 51.8 (#103)

Multilingual benchmarks
BenchmarkClaude Fable 5.1Grok 4
LMArena Non-English15071403
LMArena Chinese15861427
LMArena French15251418
LMArena German15001429
LMArena Japanese15431394
LMArena Korean15341377
LMArena Russian15211410
LMArena Spanish15161420

Instruction Following Too close to call

Claude Fable 5.1: 79.2 (#6), Grok 4: 79.2 (#5)

Instruction Following benchmarks
BenchmarkClaude Fable 5.1Grok 4
LMArena Instruction Following15171387
IFEval—94.9%

Long Context Grok 4 leads

Claude Fable 5.1: 46.7 (#20), Grok 4: 63.1 (#4)

Long Context benchmarks
BenchmarkClaude Fable 5.1Grok 4
LMArena Longer Query15221409
Fiction.LiveBench—94.4%

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#2), Grok 4: 58.5 (#116)

Writing & Preference benchmarks
BenchmarkClaude Fable 5.1Grok 4
LMArena Text15101411
LMArena Creative Writing15071397
LMArena Multi-Turn14921416
Short-Story Creative Writing—76.9%
EQ-Bench Creative Writing2162—
WildBench—79.7%

Frequently asked questions

Is Claude Fable 5.1 better than Grok 4?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 48.1 on the Noometry Index.

Is Claude Fable 5.1 or Grok 4 better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 50.3 in the Noometry coding category.

How many benchmarks do Claude Fable 5.1 and Grok 4 share?

24 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and Grok 4 has 48.

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