# Grok 4 vs Grok 4 Fast

> Grok 4 is the stronger model overall, scoring 48.1 to 39.4 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-vs-grok-4-fast
- Last updated: 2026-10-10
- Shared benchmarks: 26

## Summary

- They share 26 benchmarks with published results for both. Grok 4 scores higher in 7 categories and Grok 4 Fast in 2 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Grok 4 leads 53.8 to 32.0.
- The biggest single-benchmark swing is ARC-AGI-1: 66.7% for Grok 4 and 48.5% for Grok 4 Fast.

## Snapshot

| | Grok 4 | Grok 4 Fast |
|---|---|---|
| Provider | xAI | xAI |
| Noometry Index | 48.1 | 39.4 |
| Rank | 56 | 167 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4: 50.3 (#46)
- Grok 4 Fast: 32.5 (#271)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| WeirdML | 45.7% | 42.9% |
| LMArena Coding | 1408 | 1429 |
| Aider Polyglot | 79.6% | — |
| LMArena WebDev | — | 1159 |

## Agentic & Tool Use

- Grok 4: 32.3 (#68)
- Grok 4 Fast: 29.5 (#86)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| Cybench | 43% | 30% |
| LMArena Search | 1142 | 1171 |
| Terminal-Bench | 27.2% | — |
| Berkeley Function Calling Leaderboard | 63% | — |
| GDPval | 21.1% | — |
| τ²-bench Banking | — | 15.7% |
| DeepResearch Bench | 47.3% | — |
| BALROG | 43.6% | — |
| METR Time Horizons | 66.6% | — |

## Reasoning

- Grok 4: 36.7 (#65)
- Grok 4 Fast: 22.2 (#201)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 16% | 5.3% |
| Kagi LLM Benchmark | 73.6% | 66.1% |
| ARC-AGI-1 | 66.7% | 48.5% |
| LMArena Hard Prompts | 1409 | 1412 |
| Epoch Capabilities Index | 146.44 | 144.2 |
| ForecastBench | 60.9 | 60.5 |
| SimpleBench | 60.5% | — |
| Chess Puzzles | 28% | — |
| DTBench | — | 82.7% |

## Math

- Grok 4: 48.4 (#64)
- Grok 4 Fast: 38.9 (#123)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1422 | 1419 |
| OTIS Mock AIME 2024-2025 | 84% | — |
| Omni-MATH | 60.3% | — |
| FrontierMath (Feb 2025 set) | 19.7% | — |
| FrontierMath Tier 4 (v1) | 2.1% | — |

## Knowledge

- Grok 4: 53.8 (#55)
- Grok 4 Fast: 32.0 (#214)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1415 | 1411 |
| GPQA Diamond | 87% | — |
| MMLU-Pro | 85.1% | — |
| Confabulations | 12.4% | — |
| Vectara Hallucination Rate | — | 19.7% |
| GPQA (HELM) | 72.7% | — |

## Multimodal

- Grok 4: 33.7 (#94)
- Grok 4 Fast: —

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1210 | — |
| GeoBench | 45% | — |

## Multilingual

- Grok 4: 51.8 (#103)
- Grok 4 Fast: 51.3 (#111)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1403 | 1396 |
| LMArena Chinese | 1427 | 1457 |
| LMArena French | 1418 | 1431 |
| LMArena German | 1429 | 1383 |
| LMArena Japanese | 1394 | 1352 |
| LMArena Korean | 1377 | 1357 |
| LMArena Russian | 1410 | 1389 |
| LMArena Spanish | 1420 | 1415 |

## Instruction Following

- Grok 4: 79.2 (#5)
- Grok 4 Fast: 73.2 (#121)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1387 | 1387 |
| IFEval | 94.9% | — |

## Long Context

- Grok 4: 63.1 (#4)
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| Fiction.LiveBench | 94.4% | 94.4% |
| LMArena Longer Query | 1409 | 1415 |

## Writing & Preference

- Grok 4: 58.5 (#116)
- Grok 4 Fast: 60.0 (#102)

| Benchmark | Grok 4 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1411 | 1407 |
| LMArena Creative Writing | 1397 | 1387 |
| LMArena Multi-Turn | 1416 | 1414 |
| Short-Story Creative Writing | 76.9% | — |
| WildBench | 79.7% | — |

## FAQ

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

Grok 4 is the stronger model overall, scoring 48.1 to 39.4 on the Noometry Index.

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

Grok 4 scores higher on coding benchmarks: 50.3 versus 32.5 in the Noometry coding category.

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

26 benchmarks have published results for both models. Grok 4 has 48 scored results on Noometry and Grok 4 Fast has 30.