# Grok 4.1 Fast vs Hy4 preview

> Hy4 preview is the stronger model overall, scoring 44.6 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 4.5× less per token, which makes it the better buy when Hy4 preview's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/grok-4-1-fast-vs-hy4-preview
- Last updated: 2026-10-10
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. Grok 4.1 Fast scores higher in 1 category and Hy4 preview in 2 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where Hy4 preview leads 54.5 to 30.9.
- The biggest single-benchmark swing is ProofBench: 4% for Grok 4.1 Fast and 75% for Hy4 preview.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $0.83 / $2.50 for Hy4 preview.
- Hy4 preview accepts more context: 1.05M tokens versus 128K.
- Hy4 preview has downloadable open weights; the other is API-only.

## Snapshot

| | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| Provider | xAI | Tencent |
| Noometry Index | 40.9 | 44.6 |
| Rank | 131 | 73 |
| Context | 128K | 1.05M |
| Input $/M | $0.20 | $0.83 |
| Output $/M | $0.50 | $2.50 |
| Weights | Proprietary | Open |

## Coding

- Grok 4.1 Fast: 33.8 (#236)
- Hy4 preview: 51.4 (#36)

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena WebDev | 1241 | 1633 |
| LMArena Coding | 1411 | — |
| ALE-Bench | 394.93 | — |

## Agentic & Tool Use

- Grok 4.1 Fast: 36.1 (#35)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| Berkeley Function Calling Leaderboard | 69.6% | — |
| τ²-bench Banking | 13.1% | — |
| LMArena Search | 1171 | — |
| Vending-Bench 2 | 1,107 | — |

## Reasoning

- Grok 4.1 Fast: 42.3 (#45)
- Hy4 preview: 30.6 (#75)

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| NYT Connections (extended) | 87.4% | 68.2% |
| SimpleBench | 56% | — |
| LMArena Hard Prompts | 1407 | — |
| DTBench | 87.7% | — |
| ForecastBench | 61 | — |

## Math

- Grok 4.1 Fast: 30.9 (#201)
- Hy4 preview: 54.5 (#37)

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| ProofBench | 4% | 75% |
| MathArena Final-Answer Competitions | 60.9% | — |
| LMArena Math | 1408 | — |

## Knowledge

- Grok 4.1 Fast: 32.6 (#203)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| Vectara Hallucination Rate | 17.8% | — |
| LMArena Expert | 1398 | — |

## Multimodal

- Grok 4.1 Fast: 36.3 (#71)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Vision | 1201 | — |

## Multilingual

- Grok 4.1 Fast: 51.1 (#110)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Non-English | 1391 | — |
| LMArena Chinese | 1441 | — |
| LMArena French | 1416 | — |
| LMArena German | 1404 | — |
| LMArena Japanese | 1347 | — |
| LMArena Korean | 1361 | — |
| LMArena Russian | 1387 | — |
| LMArena Spanish | 1411 | — |

## Instruction Following

- Grok 4.1 Fast: 72.8 (#127)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Instruction Following | 1376 | — |

## Long Context

- Grok 4.1 Fast: 42.4 (#121)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Longer Query | 1390 | — |

## Writing & Preference

- Grok 4.1 Fast: 57.4 (#126)
- Hy4 preview: —

| Benchmark | Grok 4.1 Fast | Hy4 preview |
|---|---|---|
| LMArena Text | 1408 | — |
| LMArena Creative Writing | 1394 | — |
| EQ-Bench Creative Writing | 1327 | — |
| LMArena Multi-Turn | 1389 | — |

## FAQ

### Is Grok 4.1 Fast better than Hy4 preview?

Hy4 preview is the stronger model overall, scoring 44.6 to 40.9 on the Noometry Index. Grok 4.1 Fast costs 4.5× less per token, which makes it the better buy when Hy4 preview's lead doesn't matter for your workload.

### Which is cheaper, Grok 4.1 Fast or Hy4 preview?

Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Hy4 preview lists at $0.83 and $2.50.

### Is Grok 4.1 Fast or Hy4 preview better for coding?

Hy4 preview scores higher on coding benchmarks: 51.4 versus 33.8 in the Noometry coding category.

### Which has the bigger context window?

Hy4 preview does, with 1.05M tokens against 128K.

### How many benchmarks do Grok 4.1 Fast and Hy4 preview share?

3 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Hy4 preview has 3.