# Grok 4 Fast vs Mistral Medium 3.5

> Grok 4 Fast and Mistral Medium 3.5 score almost the same on the Noometry Index (39.4 vs 40.2), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/grok-4-fast-vs-mistral-medium-3-5
- Last updated: 2026-10-10
- Shared benchmarks: 19

## Summary

- They share 19 benchmarks with published results for both. Grok 4 Fast scores higher in 3 categories and Mistral Medium 3.5 in 5 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 43.2.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 66.1% for Grok 4 Fast and 41.4% for Mistral Medium 3.5.
- Mistral Medium 3.5 has downloadable open weights; the other is API-only.

## Snapshot

| | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| Provider | xAI | Mistral AI |
| Noometry Index | 39.4 | 40.2 |
| Rank | 167 | 152 |
| Context | — | 262K |
| Input $/M | — | $1.50 |
| Output $/M | — | $7.50 |
| Weights | Proprietary | Open |

## Coding

- Grok 4 Fast: 32.5 (#271)
- Mistral Medium 3.5: 36.0 (#213)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena WebDev | 1159 | 1264 |
| LMArena Coding | 1429 | 1461 |
| WeirdML | 42.9% | — |

## Agentic & Tool Use

- Grok 4 Fast: 29.5 (#86)
- Mistral Medium 3.5: —

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |

## Reasoning

- Grok 4 Fast: 22.2 (#201)
- Mistral Medium 3.5: 17.3 (#295)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| Kagi LLM Benchmark | 66.1% | 41.4% |
| LMArena Hard Prompts | 1412 | 1436 |
| Epoch Capabilities Index | 144.2 | 141.35 |
| ARC-AGI-2 | 5.3% | — |
| NYT Connections (extended) | — | 12.9% |
| ARC-AGI-1 | 48.5% | — |
| DTBench | 82.7% | — |
| ForecastBench | 60.5 | — |

## Math

- Grok 4 Fast: 38.9 (#123)
- Mistral Medium 3.5: 39.1 (#113)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Math | 1419 | 1431 |

## Knowledge

- Grok 4 Fast: 32.0 (#214)
- Mistral Medium 3.5: 40.0 (#126)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Expert | 1411 | 1432 |
| Vectara Hallucination Rate | 19.7% | — |

## Multimodal

- Grok 4 Fast: —
- Mistral Medium 3.5: 38.3 (#65)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Vision | — | 1223 |

## Multilingual

- Grok 4 Fast: 51.3 (#111)
- Mistral Medium 3.5: 51.9 (#100)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Non-English | 1396 | 1404 |
| LMArena Chinese | 1457 | 1442 |
| LMArena French | 1431 | 1448 |
| LMArena German | 1383 | 1451 |
| LMArena Korean | 1357 | 1385 |
| LMArena Russian | 1389 | 1395 |
| LMArena Spanish | 1415 | 1409 |
| LMArena Japanese | 1352 | — |

## Instruction Following

- Grok 4 Fast: 73.2 (#121)
- Mistral Medium 3.5: 74.6 (#90)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Instruction Following | 1387 | 1415 |

## Long Context

- Grok 4 Fast: 63.2 (#3)
- Mistral Medium 3.5: 43.2 (#103)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Longer Query | 1415 | 1415 |
| Fiction.LiveBench | 94.4% | — |

## Writing & Preference

- Grok 4 Fast: 60.0 (#102)
- Mistral Medium 3.5: 58.5 (#117)

| Benchmark | Grok 4 Fast | Mistral Medium 3.5 |
|---|---|---|
| LMArena Text | 1407 | 1421 |
| LMArena Creative Writing | 1387 | 1374 |
| LMArena Multi-Turn | 1414 | 1423 |
| EQ-Bench 4 | — | 993 |

## FAQ

### Is Grok 4 Fast better than Mistral Medium 3.5?

Grok 4 Fast and Mistral Medium 3.5 score almost the same on the Noometry Index (39.4 vs 40.2), so choose on price, context window or the category you care about most.

### Is Grok 4 Fast or Mistral Medium 3.5 better for coding?

Mistral Medium 3.5 scores higher on coding benchmarks: 36.0 versus 32.5 in the Noometry coding category.

### How many benchmarks do Grok 4 Fast and Mistral Medium 3.5 share?

19 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Mistral Medium 3.5 has 22.