Noometry

Model comparison

Grok 4.1 Fast vs MiMo-V2.5

MiMo-V2.5 is the stronger model overall, scoring 43.4 to 41.4 on the Noometry Index.

Last verified . 21 shared benchmarks.

Grok 4.1 Fast xAI

41.4

Rank #136 Confirmed

MiMo-V2.5 Xiaomi

43.4

Rank #93 Confirmed

Summary

  • They share 21 benchmarks with published results for both. Grok 4.1 Fast scores higher in 1 category and MiMo-V2.5 in 8 categories; 8 gaps are clear of the uncertainty.
  • The widest gap is in reasoning, where Grok 4.1 Fast leads 43.4 to 28.6.
  • The biggest single-benchmark swing is ProofBench: 4% for Grok 4.1 Fast and 16% for MiMo-V2.5.
  • MiMo-V2.5 is cheaper at $0.14 / $0.28 per million input/output tokens, against $0.20 / $0.50 for Grok 4.1 Fast.
  • MiMo-V2.5 accepts more context: 1.05M tokens versus 128K.
  • MiMo-V2.5 has downloadable open weights; the other is API-only.

Side by side

Grok 4.1 FastMiMo-V2.5
ProviderxAIXiaomi
Noometry Index41.443.4
Released2025-06-272026-04-22
WeightsProprietaryOpen
Context window128K1.05M
Max output30K131K
Input $ / M tokens$0.20$0.14
Output $ / M tokens$0.50$0.28
Results tracked3223

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Category by category

Coding MiMo-V2.5 leads

Grok 4.1 Fast: 34.1 (#245), MiMo-V2.5: 43.9 (#81)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena WebDev12421438
LMArena Coding14111469
ALE-Bench394.93513.95
SciCode—43.1%

Agentic & Tool Use Not comparable

Grok 4.1 Fast: 36.3 (#39), MiMo-V2.5: —

BenchmarkGrok 4.1 FastMiMo-V2.5
Berkeley Function Calling Leaderboard69.6%—
τ²-bench Banking13.1%—
LMArena Search1171—
Vending-Bench 21,107—

Reasoning Grok 4.1 Fast leads

Grok 4.1 Fast: 43.4 (#49), MiMo-V2.5: 28.6 (#101)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Hard Prompts14071450
SimpleBench56%—
NYT Connections (extended)87.4%—
CritPt—3.7%
DTBench87.7%—
ForecastBench61—

Math MiMo-V2.5 leads

Grok 4.1 Fast: 31.9 (#221), MiMo-V2.5: 36.8 (#163)

BenchmarkGrok 4.1 FastMiMo-V2.5
ProofBench4%16%
LMArena Math14081436
MathArena Final-Answer Competitions60.9%—

Knowledge MiMo-V2.5 leads

Grok 4.1 Fast: 33.1 (#207), MiMo-V2.5: 40.8 (#115)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Expert13991460
Vectara Hallucination Rate17.8%—

Multimodal MiMo-V2.5 leads

Grok 4.1 Fast: 37.0 (#76), MiMo-V2.5: 39.8 (#54)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Vision12011247

Multilingual Too close to call

Grok 4.1 Fast: 51.0 (#114), MiMo-V2.5: 51.9 (#99)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Non-English13911404
LMArena Chinese14411468
LMArena French14151447
LMArena German14041421
LMArena Japanese13491306
LMArena Korean13611363
LMArena Russian13871395
LMArena Spanish14131416

Instruction Following MiMo-V2.5 leads

Grok 4.1 Fast: 72.7 (#133), MiMo-V2.5: 75.5 (#60)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Instruction Following13761434

Long Context MiMo-V2.5 leads

Grok 4.1 Fast: 42.4 (#126), MiMo-V2.5: 44.2 (#73)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Longer Query13901445

Writing & Preference MiMo-V2.5 leads

Grok 4.1 Fast: 57.2 (#131), MiMo-V2.5: 61.6 (#86)

BenchmarkGrok 4.1 FastMiMo-V2.5
LMArena Text14081428
LMArena Creative Writing13941393
LMArena Multi-Turn13891445
EQ-Bench Creative Writing1327—

Frequently asked questions

Is Grok 4.1 Fast better than MiMo-V2.5?

MiMo-V2.5 is the stronger model overall, scoring 43.4 to 41.4 on the Noometry Index.

Which is cheaper, Grok 4.1 Fast or MiMo-V2.5?

MiMo-V2.5 is cheaper. It lists at $0.14 per million input tokens and $0.28 per million output tokens; Grok 4.1 Fast lists at $0.20 and $0.50.

Is Grok 4.1 Fast or MiMo-V2.5 better for coding?

MiMo-V2.5 scores higher on coding benchmarks: 43.9 versus 34.1 in the Noometry coding category.

Which has the bigger context window?

MiMo-V2.5 does, with 1.05M tokens against 128K.

How many benchmarks do Grok 4.1 Fast and MiMo-V2.5 share?

21 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and MiMo-V2.5 has 23.

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