Model comparison

Grok 4 Fast vs Phi 3 Mini 128k Instruct

Grok 4 Fast is the stronger model overall, scoring 39.4 to 29.7 on the Noometry Index.

Last verified . 17 shared benchmarks.

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

Phi 3 Mini 128k Instruct Microsoft

29.7

Rank #305 Confirmed

Summary

  • They share 17 benchmarks with published results for both. Grok 4 Fast scores higher in 8 categories and Phi 3 Mini 128k Instruct in 0 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 30.4.
  • Phi 3 Mini 128k Instruct has downloadable open weights; the other is API-only.

Side by side

Grok 4 Fast and Phi 3 Mini 128k Instruct specifications
Grok 4 FastPhi 3 Mini 128k Instruct
ProviderxAIMicrosoft
Noometry Index39.429.7
Released2025-09-192024-04-23
WeightsProprietaryOpen
Context window——
Max output——
Input $ / M tokens——
Output $ / M tokens——
Results tracked3019

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Category by category

Coding Grok 4 Fast leads

Grok 4 Fast: 32.5 (#271), Phi 3 Mini 128k Instruct: 28.8 (#312)

Coding benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Coding14291039
LMArena WebDev1159—
WeirdML42.9%—
BigCodeBench Instruct—29.6%
BigCodeBench Complete—40.6%

Agentic & Tool Use Not comparable

Grok 4 Fast: 29.5 (#86), Phi 3 Mini 128k Instruct: —

Agentic & Tool Use benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
τ²-bench Banking15.7%—
Cybench30%—
LMArena Search1171—

Reasoning Grok 4 Fast leads

Grok 4 Fast: 22.2 (#201), Phi 3 Mini 128k Instruct: 19.6 (#256)

Reasoning benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Hard Prompts14121028
ARC-AGI-25.3%—
Kagi LLM Benchmark66.1%—
ARC-AGI-148.5%—
DTBench82.7%—
Epoch Capabilities Index144.2—
ForecastBench60.5—

Math Grok 4 Fast leads

Grok 4 Fast: 38.9 (#123), Phi 3 Mini 128k Instruct: 31.6 (#222)

Math benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Math14191089

Knowledge Grok 4 Fast leads

Grok 4 Fast: 32.0 (#214), Phi 3 Mini 128k Instruct: 26.8 (#254)

Knowledge benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Expert1411984
Vectara Hallucination Rate19.7%—

Multilingual Grok 4 Fast leads

Grok 4 Fast: 51.3 (#111), Phi 3 Mini 128k Instruct: 25.2 (#285)

Multilingual benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Non-English13961000
LMArena Chinese14571016
LMArena French14311039
LMArena German13831006
LMArena Japanese1352899
LMArena Korean1357856
LMArena Russian13891004
LMArena Spanish14151059

Instruction Following Grok 4 Fast leads

Grok 4 Fast: 73.2 (#121), Phi 3 Mini 128k Instruct: 51.8 (#294)

Instruction Following benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Instruction Following13871023

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), Phi 3 Mini 128k Instruct: 30.4 (#289)

Long Context benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Longer Query1415996
Fiction.LiveBench94.4%—

Writing & Preference Grok 4 Fast leads

Grok 4 Fast: 60.0 (#102), Phi 3 Mini 128k Instruct: 27.1 (#301)

Writing & Preference benchmarks
BenchmarkGrok 4 FastPhi 3 Mini 128k Instruct
LMArena Text14071050
LMArena Creative Writing13871024
LMArena Multi-Turn1414989

Frequently asked questions

Is Grok 4 Fast better than Phi 3 Mini 128k Instruct?

Grok 4 Fast is the stronger model overall, scoring 39.4 to 29.7 on the Noometry Index.

Is Grok 4 Fast or Phi 3 Mini 128k Instruct better for coding?

Grok 4 Fast scores higher on coding benchmarks: 32.5 versus 28.8 in the Noometry coding category.

How many benchmarks do Grok 4 Fast and Phi 3 Mini 128k Instruct share?

17 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Phi 3 Mini 128k Instruct has 19.

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