Model comparison

Grok 4 Fast vs MiMo-V2-Flash

MiMo-V2-Flash is the stronger model overall, scoring 41.3 to 39.4 on the Noometry Index.

Last verified . 18 shared benchmarks.

Grok 4 Fast xAI

39.4

Rank #167 Confirmed

MiMo-V2-Flash Xiaomi

41.3

Rank #138 Confirmed

Summary

  • They share 18 benchmarks with published results for both. Grok 4 Fast scores higher in 4 categories and MiMo-V2-Flash in 4 categories; 4 gaps are clear of the uncertainty.
  • The widest gap is in long context, where Grok 4 Fast leads 63.2 to 43.0.
  • MiMo-V2-Flash has downloadable open weights; the other is API-only.

Side by side

Grok 4 Fast and MiMo-V2-Flash specifications
Grok 4 FastMiMo-V2-Flash
ProviderxAIXiaomi
Noometry Index39.441.3
Released2025-09-192025-12-16
WeightsProprietaryOpen
Context window—262K
Max output—66K
Input $ / M tokens—$0.14
Output $ / M tokens—$0.28
Results tracked3021

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Category by category

Coding MiMo-V2-Flash leads

Grok 4 Fast: 32.5 (#271), MiMo-V2-Flash: 36.1 (#211)

Coding benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena WebDev11591330
LMArena Coding14291443
SciCode—25.9%
WeirdML42.9%—
ALE-Bench—737.95

Agentic & Tool Use Not comparable

Grok 4 Fast: 29.5 (#86), MiMo-V2-Flash: —

Agentic & Tool Use benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
τ²-bench Banking15.7%—
Cybench30%—
LMArena Search1171—

Reasoning MiMo-V2-Flash leads

Grok 4 Fast: 22.2 (#201), MiMo-V2-Flash: 24.9 (#157)

Reasoning benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Hard Prompts14121420
ARC-AGI-25.3%—
Kagi LLM Benchmark66.1%—
ARC-AGI-148.5%—
CritPt—0%
DTBench82.7%—
Epoch Capabilities Index144.2—
ForecastBench60.5—

Math Too close to call

Grok 4 Fast: 38.9 (#123), MiMo-V2-Flash: 38.3 (#139)

Math benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Math14191396

Knowledge MiMo-V2-Flash leads

Grok 4 Fast: 32.0 (#214), MiMo-V2-Flash: 39.7 (#131)

Knowledge benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Expert14111425
Vectara Hallucination Rate19.7%—

Multilingual Too close to call

Grok 4 Fast: 51.3 (#111), MiMo-V2-Flash: 51.0 (#113)

Multilingual benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Non-English13961392
LMArena Chinese14571462
LMArena French14311429
LMArena German13831395
LMArena Japanese13521325
LMArena Korean13571358
LMArena Russian13891387
LMArena Spanish14151420

Instruction Following Too close to call

Grok 4 Fast: 73.2 (#121), MiMo-V2-Flash: 73.5 (#120)

Instruction Following benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Instruction Following13871392

Long Context Grok 4 Fast leads

Grok 4 Fast: 63.2 (#3), MiMo-V2-Flash: 43.0 (#110)

Long Context benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Longer Query14151409
Fiction.LiveBench94.4%—

Writing & Preference Too close to call

Grok 4 Fast: 60.0 (#102), MiMo-V2-Flash: 59.7 (#106)

Writing & Preference benchmarks
BenchmarkGrok 4 FastMiMo-V2-Flash
LMArena Text14071411
LMArena Creative Writing13871375
LMArena Multi-Turn14141404

Frequently asked questions

Is Grok 4 Fast better than MiMo-V2-Flash?

MiMo-V2-Flash is the stronger model overall, scoring 41.3 to 39.4 on the Noometry Index.

Is Grok 4 Fast or MiMo-V2-Flash better for coding?

MiMo-V2-Flash scores higher on coding benchmarks: 36.1 versus 32.5 in the Noometry coding category.

How many benchmarks do Grok 4 Fast and MiMo-V2-Flash share?

18 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and MiMo-V2-Flash has 21.

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