Noometry

Model comparison

Grok 4 vs Grok 4 Fast

Grok 4 is the stronger model overall, scoring 48.1 to 39.4 on the Noometry Index.

Last verified . 26 shared benchmarks.

Grok 4 xAI

48.1

Rank #56 Confirmed

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Summary

  • They share 26 benchmarks with published results for both. Grok 4 scores higher in 7 categories and Grok 4 Fast in 2 categories; 7 gaps are clear of the uncertainty.
  • The widest gap is in knowledge, where Grok 4 leads 53.8 to 32.0.
  • The biggest single-benchmark swing is ARC-AGI-1: 66.7% for Grok 4 and 48.5% for Grok 4 Fast.

Side by side

Grok 4Grok 4 Fast
ProviderxAIxAI
Noometry Index48.139.4
Released2025-07-092025-09-19
WeightsProprietaryProprietary
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked4830

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Category by category

Coding Grok 4 leads

Grok 4: 50.3 (#46), Grok 4 Fast: 32.5 (#271)

BenchmarkGrok 4Grok 4 Fast
WeirdML45.7%42.9%
LMArena Coding14081429
Aider Polyglot79.6%—
LMArena WebDev—1159

Agentic & Tool Use Grok 4 leads

Grok 4: 32.3 (#68), Grok 4 Fast: 29.5 (#86)

BenchmarkGrok 4Grok 4 Fast
Cybench43%30%
LMArena Search11421171
Terminal-Bench27.2%—
Berkeley Function Calling Leaderboard63%—
GDPval21.1%—
τ²-bench Banking—15.7%
DeepResearch Bench47.3%—
BALROG43.6%—
METR Time Horizons66.6%—

Reasoning Grok 4 leads

Grok 4: 36.7 (#65), Grok 4 Fast: 22.2 (#201)

BenchmarkGrok 4Grok 4 Fast
ARC-AGI-216%5.3%
Kagi LLM Benchmark73.6%66.1%
ARC-AGI-166.7%48.5%
LMArena Hard Prompts14091412
Epoch Capabilities Index146.44144.2
ForecastBench60.960.5
SimpleBench60.5%—
Chess Puzzles28%—
DTBench—82.7%

Math Grok 4 leads

Grok 4: 48.4 (#64), Grok 4 Fast: 38.9 (#123)

BenchmarkGrok 4Grok 4 Fast
LMArena Math14221419
OTIS Mock AIME 2024-202584%—
Omni-MATH60.3%—
FrontierMath (Feb 2025 set)19.7%—
FrontierMath Tier 4 (v1)2.1%—

Knowledge Grok 4 leads

Grok 4: 53.8 (#55), Grok 4 Fast: 32.0 (#214)

BenchmarkGrok 4Grok 4 Fast
LMArena Expert14151411
GPQA Diamond87%—
MMLU-Pro85.1%—
Confabulations12.4%—
Vectara Hallucination Rate—19.7%
GPQA (HELM)72.7%—

Multimodal Not comparable

Grok 4: 33.7 (#94), Grok 4 Fast: —

BenchmarkGrok 4Grok 4 Fast
LMArena Vision1210—
GeoBench45%—

Multilingual Too close to call

Grok 4: 51.8 (#103), Grok 4 Fast: 51.3 (#111)

BenchmarkGrok 4Grok 4 Fast
LMArena Non-English14031396
LMArena Chinese14271457
LMArena French14181431
LMArena German14291383
LMArena Japanese13941352
LMArena Korean13771357
LMArena Russian14101389
LMArena Spanish14201415

Instruction Following Grok 4 leads

Grok 4: 79.2 (#5), Grok 4 Fast: 73.2 (#121)

BenchmarkGrok 4Grok 4 Fast
LMArena Instruction Following13871387
IFEval94.9%—

Long Context Too close to call

Grok 4: 63.1 (#4), Grok 4 Fast: 63.2 (#3)

BenchmarkGrok 4Grok 4 Fast
Fiction.LiveBench94.4%94.4%
LMArena Longer Query14091415

Writing & Preference Grok 4 Fast leads

Grok 4: 58.5 (#116), Grok 4 Fast: 60.0 (#102)

BenchmarkGrok 4Grok 4 Fast
LMArena Text14111407
LMArena Creative Writing13971387
LMArena Multi-Turn14161414
Short-Story Creative Writing76.9%—
WildBench79.7%—

Frequently asked questions

Is Grok 4 better than Grok 4 Fast?

Grok 4 is the stronger model overall, scoring 48.1 to 39.4 on the Noometry Index.

Is Grok 4 or Grok 4 Fast better for coding?

Grok 4 scores higher on coding benchmarks: 50.3 versus 32.5 in the Noometry coding category.

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

26 benchmarks have published results for both models. Grok 4 has 48 scored results on Noometry and Grok 4 Fast has 30.

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