Model comparison

Grok 4 Fast vs o4-mini

o4-mini is the stronger model overall, scoring 41.6 to 39.4 on the Noometry Index.

Last verified . 26 shared benchmarks.

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

o4-mini OpenAI

41.6

Rank #132 Confirmed

Summary

  • They share 26 benchmarks with published results for both. Grok 4 Fast scores higher in 3 categories and o4-mini in 6 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 45.5.
  • The biggest single-benchmark swing is Fiction.LiveBench: 94.4% for Grok 4 Fast and 77.8% for o4-mini.

Side by side

Grok 4 Fast and o4-mini specifications
Grok 4 Fasto4-mini
ProviderxAIOpenAI
Noometry Index39.441.6
Released2025-09-192025-04-16
WeightsProprietaryProprietary
Context window—200K
Max output—100K
Input $ / M tokens—$1.10
Output $ / M tokens—$4.40
Results tracked3060

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Category by category

Coding o4-mini leads

Grok 4 Fast: 32.5 (#271), o4-mini: 40.9 (#127)

Coding benchmarks
BenchmarkGrok 4 Fasto4-mini
WeirdML42.9%52.6%
LMArena Coding14291368
SWE-bench Verified (bash only)—45%
Aider Polyglot—72%
LMArena WebDev1159—
GSO—3.6%
CadEval—62%
ALE-Bench—826.17
AlgoTune—1.72

Agentic & Tool Use o4-mini leads

Grok 4 Fast: 29.5 (#86), o4-mini: 32.6 (#61)

Agentic & Tool Use benchmarks
BenchmarkGrok 4 Fasto4-mini
Berkeley Function Calling Leaderboard—53.2%
GDPval—25.3%
τ²-bench Banking15.7%—
Cybench30%—
LMArena Search1171—
METR Time Horizons—63.9%

Reasoning o4-mini leads

Grok 4 Fast: 22.2 (#201), o4-mini: 24.6 (#162)

Reasoning benchmarks
BenchmarkGrok 4 Fasto4-mini
ARC-AGI-25.3%6.1%
Kagi LLM Benchmark66.1%67.6%
ARC-AGI-148.5%58.7%
LMArena Hard Prompts14121351
DTBench82.7%77.6%
Epoch Capabilities Index144.2145.64
ForecastBench60.561.8
SimpleBench—38.7%
CritPt—0.6%
Chess Puzzles—26%
EnigmaEval—9.2%
Mystery Game Puzzles—5%
LMCA—26.5%

Math o4-mini leads

Grok 4 Fast: 38.9 (#123), o4-mini: 40.8 (#89)

Math benchmarks
BenchmarkGrok 4 Fasto4-mini
LMArena Math14191389
FrontierMath (Tiers 1-3)—36.1%
FrontierMath Tier 4—4.9%
OTIS Mock AIME 2024-2025—81.7%
Omni-MATH—72%
MATH Level 5—97.8%
FrontierMath (Feb 2025 set)—24.8%
FrontierMath Tier 4 (v1)—6.3%

Knowledge o4-mini leads

Grok 4 Fast: 32.0 (#214), o4-mini: 43.6 (#91)

Knowledge benchmarks
BenchmarkGrok 4 Fasto4-mini
Vectara Hallucination Rate19.7%18.6%
LMArena Expert14111343
GPQA Diamond—79.6%
Humanity's Last Exam—18.1%
SimpleQA Verified—19.6%
MMLU-Pro—82%
Confabulations—15.8%
GPQA (HELM)—73.5%

Multimodal Not comparable

Grok 4 Fast: —, o4-mini: 40.2 (#49)

Multimodal benchmarks
BenchmarkGrok 4 Fasto4-mini
LMArena Vision—1194
GeoBench—64%
VPCT—57.5%

Multilingual Grok 4 Fast leads

Grok 4 Fast: 51.3 (#111), o4-mini: 47.0 (#154)

Multilingual benchmarks
BenchmarkGrok 4 Fasto4-mini
LMArena Non-English13961337
LMArena Chinese14571354
LMArena French14311364
LMArena German13831336
LMArena Japanese13521308
LMArena Korean13571312
LMArena Russian13891334
LMArena Spanish14151347

Instruction Following o4-mini leads

Grok 4 Fast: 73.2 (#121), o4-mini: 75.2 (#68)

Instruction Following benchmarks
BenchmarkGrok 4 Fasto4-mini
LMArena Instruction Following13871321
IFEval—92.8%

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), o4-mini: 45.5 (#33)

Long Context benchmarks
BenchmarkGrok 4 Fasto4-mini
Fiction.LiveBench94.4%77.8%
LMArena Longer Query14151315

Writing & Preference Grok 4 Fast leads

Grok 4 Fast: 60.0 (#102), o4-mini: 54.0 (#152)

Writing & Preference benchmarks
BenchmarkGrok 4 Fasto4-mini
LMArena Text14071353
LMArena Creative Writing13871294
LMArena Multi-Turn14141350
Short-Story Creative Writing—75%
WildBench—85.4%

Frequently asked questions

Is Grok 4 Fast better than o4-mini?

o4-mini is the stronger model overall, scoring 41.6 to 39.4 on the Noometry Index.

Is Grok 4 Fast or o4-mini better for coding?

o4-mini scores higher on coding benchmarks: 40.9 versus 32.5 in the Noometry coding category.

How many benchmarks do Grok 4 Fast and o4-mini share?

26 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and o4-mini has 60.

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