# Grok 4 Fast vs Sonar

> Grok 4 Fast is the stronger model overall, scoring 39.0 to 37.8 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-fast-vs-sonar
- Last updated: 2026-10-10
- Shared benchmarks: 0

## Summary

- The widest gap is in writing & preference, where Grok 4 Fast leads 60.2 to 52.6.

## Snapshot

| | Grok 4 Fast | Sonar |
|---|---|---|
| Provider | xAI | Perplexity |
| Noometry Index | 39.0 | 37.8 |
| Rank | 164 | 184 |
| Context | — | 128K |
| Input $/M | — | $1 |
| Output $/M | — | $1 |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4 Fast: 32.3 (#264)
- Sonar: 35.1 (#217)

| Benchmark | Grok 4 Fast | Sonar |
|---|---|---|
| LMArena WebDev | 1160 | — |
| WeirdML | 42.9% | — |
| LiveBench Coding | — | 35.1% |
| LMArena Coding | 1429 | — |

## Agentic & Tool Use

- Grok 4 Fast: 29.3 (#80)
- Sonar: —

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

## Reasoning

- Grok 4 Fast: 22.5 (#179)
- Sonar: 20.3 (#221)

| Benchmark | Grok 4 Fast | Sonar |
|---|---|---|
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| LiveBench Reasoning | — | 46.3% |
| LMArena Hard Prompts | 1413 | — |
| DTBench | 82.7% | — |
| LiveBench Data Analysis | — | 37.9% |
| Epoch Capabilities Index | 144.21 | — |
| ForecastBench | 60.5 | — |
| LiveBench | — | 46.9% |

## Math

- Grok 4 Fast: 36.1 (#126)
- Sonar: 31.3 (#197)

| Benchmark | Grok 4 Fast | Sonar |
|---|---|---|
| LiveBench Math | — | 41.6% |
| LMArena Math | 1419 | — |

## Knowledge

- Grok 4 Fast: 31.5 (#211)
- Sonar: —

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

## Multilingual

- Grok 4 Fast: 51.5 (#106)
- Sonar: —

| Benchmark | Grok 4 Fast | Sonar |
|---|---|---|
| LMArena Non-English | 1397 | — |
| LMArena Chinese | 1458 | — |
| LMArena French | 1433 | — |
| LMArena German | 1383 | — |
| LMArena Japanese | 1358 | — |
| LMArena Korean | 1359 | — |
| LMArena Russian | 1387 | — |
| LMArena Spanish | 1414 | — |

## Instruction Following

- Grok 4 Fast: 73.4 (#116)
- Sonar: 71.5 (#146)

| Benchmark | Grok 4 Fast | Sonar |
|---|---|---|
| LiveBench Instruction Following | — | 76.2% |
| LMArena Instruction Following | 1388 | — |

## Long Context

- Grok 4 Fast: 63.2 (#3)
- Sonar: —

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

## Writing & Preference

- Grok 4 Fast: 60.2 (#96)
- Sonar: 52.6 (#166)

| Benchmark | Grok 4 Fast | Sonar |
|---|---|---|
| LMArena Text | 1407 | — |
| LMArena Creative Writing | 1388 | — |
| LMArena Multi-Turn | 1414 | — |
| LiveBench Language | — | 44.1% |

## FAQ

### Is Grok 4 Fast better than Sonar?

Grok 4 Fast is the stronger model overall, scoring 39.0 to 37.8 on the Noometry Index.

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

Sonar scores higher on coding benchmarks: 35.1 versus 32.3 in the Noometry coding category.

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

0 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Sonar has 7.