# 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.

- Canonical page: https://noometry.com/compare/grok-4-1-fast-vs-mimo-v2-5
- Last updated: 2026-10-12
- Shared benchmarks: 21

## 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.

## Snapshot

| | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| Provider | xAI | Xiaomi |
| Noometry Index | 41.4 | 43.4 |
| Rank | 136 | 93 |
| Context | 128K | 1.05M |
| Input $/M | $0.20 | $0.14 |
| Output $/M | $0.50 | $0.28 |
| Weights | Proprietary | Open |

## Coding

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena WebDev | 1242 | 1438 |
| LMArena Coding | 1411 | 1469 |
| ALE-Bench | 394.93 | 513.95 |
| SciCode | — | 43.1% |

## Agentic & Tool Use

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| Berkeley Function Calling Leaderboard | 69.6% | — |
| τ²-bench Banking | 13.1% | — |
| LMArena Search | 1171 | — |
| Vending-Bench 2 | 1,107 | — |

## Reasoning

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Hard Prompts | 1407 | 1450 |
| SimpleBench | 56% | — |
| NYT Connections (extended) | 87.4% | — |
| CritPt | — | 3.7% |
| DTBench | 87.7% | — |
| ForecastBench | 61 | — |

## Math

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| ProofBench | 4% | 16% |
| LMArena Math | 1408 | 1436 |
| MathArena Final-Answer Competitions | 60.9% | — |

## Knowledge

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Expert | 1399 | 1460 |
| Vectara Hallucination Rate | 17.8% | — |

## Multimodal

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Vision | 1201 | 1247 |

## Multilingual

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Non-English | 1391 | 1404 |
| LMArena Chinese | 1441 | 1468 |
| LMArena French | 1415 | 1447 |
| LMArena German | 1404 | 1421 |
| LMArena Japanese | 1349 | 1306 |
| LMArena Korean | 1361 | 1363 |
| LMArena Russian | 1387 | 1395 |
| LMArena Spanish | 1413 | 1416 |

## Instruction Following

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Instruction Following | 1376 | 1434 |

## Long Context

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Longer Query | 1390 | 1445 |

## Writing & Preference

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

| Benchmark | Grok 4.1 Fast | MiMo-V2.5 |
|---|---|---|
| LMArena Text | 1408 | 1428 |
| LMArena Creative Writing | 1394 | 1393 |
| LMArena Multi-Turn | 1389 | 1445 |
| EQ-Bench Creative Writing | 1327 | — |

## FAQ

### 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.