# Grok 4.1 vs Grok 4 Fast

> Grok 4.1 is the stronger model overall, scoring 40.8 to 39.0 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-1-vs-grok-4-fast
- Last updated: 2026-10-10
- Shared benchmarks: 19

## Summary

- They share 19 benchmarks with published results for both. Grok 4.1 scores higher in 8 categories and Grok 4 Fast in 1 category; 7 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 Cybench: 39% for Grok 4.1 and 30% for Grok 4 Fast.

## Snapshot

| | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| Provider | xAI | xAI |
| Noometry Index | 40.8 | 39.0 |
| Rank | 135 | 164 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4.1: 33.4 (#246)
- Grok 4 Fast: 32.3 (#264)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena WebDev | 1214 | 1160 |
| LMArena Coding | 1445 | 1429 |
| WeirdML | — | 42.9% |

## Agentic & Tool Use

- Grok 4.1: 33.8 (#47)
- Grok 4 Fast: 29.3 (#80)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| Cybench | 39% | 30% |
| τ²-bench Banking | — | 15.7% |
| LMArena Search | — | 1171 |

## Reasoning

- Grok 4.1: 28.3 (#91)
- Grok 4 Fast: 22.5 (#179)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Hard Prompts | 1436 | 1413 |
| ARC-AGI-2 | — | 5.3% |
| Kagi LLM Benchmark | — | 66.1% |
| ARC-AGI-1 | — | 48.5% |
| DTBench | — | 82.7% |
| Epoch Capabilities Index | — | 144.21 |
| ForecastBench | — | 60.5 |

## Math

- Grok 4.1: 36.2 (#124)
- Grok 4 Fast: 36.1 (#126)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1422 | 1419 |

## Knowledge

- Grok 4.1: 38.9 (#129)
- Grok 4 Fast: 31.5 (#211)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1417 | 1411 |
| Vectara Hallucination Rate | — | 19.7% |

## Multilingual

- Grok 4.1: 53.6 (#64)
- Grok 4 Fast: 51.5 (#106)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1425 | 1397 |
| LMArena Chinese | 1464 | 1458 |
| LMArena French | 1448 | 1433 |
| LMArena German | 1447 | 1383 |
| LMArena Japanese | 1396 | 1358 |
| LMArena Korean | 1407 | 1359 |
| LMArena Russian | 1434 | 1387 |
| LMArena Spanish | 1438 | 1414 |

## Instruction Following

- Grok 4.1: 74.0 (#106)
- Grok 4 Fast: 73.4 (#116)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1400 | 1388 |

## Long Context

- Grok 4.1: 43.2 (#96)
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1416 | 1415 |
| Fiction.LiveBench | — | 94.4% |

## Writing & Preference

- Grok 4.1: 62.6 (#71)
- Grok 4 Fast: 60.2 (#96)

| Benchmark | Grok 4.1 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1437 | 1407 |
| LMArena Creative Writing | 1411 | 1388 |
| LMArena Multi-Turn | 1438 | 1414 |

## FAQ

### Is Grok 4.1 better than Grok 4 Fast?

Grok 4.1 is the stronger model overall, scoring 40.8 to 39.0 on the Noometry Index.

### Is Grok 4.1 or Grok 4 Fast better for coding?

Grok 4.1 scores higher on coding benchmarks: 33.4 versus 32.3 in the Noometry coding category.

### How many benchmarks do Grok 4.1 and Grok 4 Fast share?

19 benchmarks have published results for both models. Grok 4.1 has 19 scored results on Noometry and Grok 4 Fast has 30.