Noometry

Model comparison

Grok 4 Fast vs Phi-4

Grok 4 Fast is the stronger model overall, scoring 39.0 to 30.9 on the Noometry Index.

Last verified . 19 shared benchmarks.

Grok 4 Fast xAI

39.0

Rank #164 Confirmed

Phi-4 Microsoft

30.9

Rank #269 Confirmed

Summary

  • They share 19 benchmarks with published results for both. Grok 4 Fast scores higher in 7 categories and Phi-4 in 2 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 36.9.
  • The biggest single-benchmark swing is Vectara Hallucination Rate: 19.7% for Grok 4 Fast and 3.7% for Phi-4.
  • Phi-4 has downloadable open weights; the other is API-only.

Side by side

Grok 4 FastPhi-4
ProviderxAIMicrosoft
Noometry Index39.030.9
Released2025-09-192024-12-11
WeightsProprietaryOpen
Context window—128K
Max output—4K
Input $ / M tokens—$0.07
Output $ / M tokens—$0.14
Results tracked3037

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Category by category

Coding Phi-4 leads

Grok 4 Fast: 32.3 (#264), Phi-4: 33.8 (#237)

BenchmarkGrok 4 FastPhi-4
LMArena Coding14291231
LMArena WebDev1160—
WeirdML42.9%—
BigCodeBench Instruct—45.5%
LiveBench Coding—30.7%
BigCodeBench Complete—55.4%

Agentic & Tool Use Grok 4 Fast leads

Grok 4 Fast: 29.3 (#80), Phi-4: 22.6 (#120)

BenchmarkGrok 4 FastPhi-4
Berkeley Function Calling Leaderboard—28.8%
τ²-bench Banking15.7%—
Cybench30%—
BALROG—11.6%
LMArena Search1171—

Reasoning Grok 4 Fast leads

Grok 4 Fast: 22.5 (#179), Phi-4: 17.0 (#287)

BenchmarkGrok 4 FastPhi-4
LMArena Hard Prompts14131220
Epoch Capabilities Index144.21130.43
ARC-AGI-25.3%—
Kagi LLM Benchmark66.1%—
ARC-AGI-148.5%—
Chess Puzzles—1%
LiveBench Reasoning—47.8%
DTBench82.7%—
LiveBench Data Analysis—45.2%
ForecastBench60.5—
LiveBench—41.6%

Math Grok 4 Fast leads

Grok 4 Fast: 36.1 (#126), Phi-4: 19.6 (#279)

BenchmarkGrok 4 FastPhi-4
LMArena Math14191246
OTIS Mock AIME 2024-2025—13.8%
LiveBench Math—42%
MATH Level 5—64.9%

Knowledge Phi-4 leads

Grok 4 Fast: 31.5 (#211), Phi-4: 32.5 (#204)

BenchmarkGrok 4 FastPhi-4
Vectara Hallucination Rate19.7%3.7%
LMArena Expert14111203
GPQA Diamond—56.1%
Confabulations—29.4%
MMLU—84.8%

Multilingual Grok 4 Fast leads

Grok 4 Fast: 51.5 (#106), Phi-4: 37.4 (#232)

BenchmarkGrok 4 FastPhi-4
LMArena Non-English13971197
LMArena Chinese14581211
LMArena French14331223
LMArena German13831222
LMArena Japanese13581158
LMArena Korean13591151
LMArena Russian13871209
LMArena Spanish14141234

Instruction Following Grok 4 Fast leads

Grok 4 Fast: 73.4 (#116), Phi-4: 60.6 (#246)

BenchmarkGrok 4 FastPhi-4
LMArena Instruction Following13881201
LiveBench Instruction Following—58.4%

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), Phi-4: 36.9 (#221)

BenchmarkGrok 4 FastPhi-4
LMArena Longer Query14151217
Fiction.LiveBench94.4%—

Writing & Preference Grok 4 Fast leads

Grok 4 Fast: 60.2 (#96), Phi-4: 40.7 (#239)

BenchmarkGrok 4 FastPhi-4
LMArena Text14071217
LMArena Creative Writing13881182
LMArena Multi-Turn14141206
Short-Story Creative Writing—62.6%
LiveBench Language—25.6%

Frequently asked questions

Is Grok 4 Fast better than Phi-4?

Grok 4 Fast is the stronger model overall, scoring 39.0 to 30.9 on the Noometry Index.

Is Grok 4 Fast or Phi-4 better for coding?

Phi-4 scores higher on coding benchmarks: 33.8 versus 32.3 in the Noometry coding category.

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

19 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Phi-4 has 37.

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