# Grok 4.20 (Non-Reasoning) vs Grok 4 Fast

> Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.5 to 39.0 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-20-vs-grok-4-fast
- Last updated: 2026-10-10
- Shared benchmarks: 27

## Summary

- They share 27 benchmarks with published results for both. Grok 4.20 (Non-Reasoning) scores higher in 8 categories and Grok 4 Fast in 1 category; 9 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.20 (Non-Reasoning) leads 52.2 to 22.5.
- The biggest single-benchmark swing is ARC-AGI-2: 65.1% for Grok 4.20 (Non-Reasoning) and 5.3% for Grok 4 Fast.

## Snapshot

| | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| Provider | xAI | xAI |
| Noometry Index | 48.5 | 39.0 |
| Rank | 48 | 164 |
| Context | 1M | — |
| Input $/M | $1.25 | — |
| Output $/M | $2.50 | — |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4.20 (Non-Reasoning): 41.8 (#104)
- Grok 4 Fast: 32.3 (#264)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena WebDev | 1374 | 1160 |
| WeirdML | 52.3% | 42.9% |
| LMArena Coding | 1458 | 1429 |
| ALE-Bench | 1,150 | — |

## Agentic & Tool Use

- Grok 4.20 (Non-Reasoning): 34.3 (#43)
- Grok 4 Fast: 29.3 (#80)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| τ²-bench Banking | 18% | 15.7% |
| LMArena Search | 1189 | 1171 |
| Terminal-Bench | 57.3% | — |
| Cybench | — | 30% |
| Vending-Bench 2 | 4,663 | — |

## Reasoning

- Grok 4.20 (Non-Reasoning): 52.2 (#30)
- Grok 4 Fast: 22.5 (#179)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 65.1% | 5.3% |
| Kagi LLM Benchmark | 75% | 66.1% |
| ARC-AGI-1 | 89.5% | 48.5% |
| LMArena Hard Prompts | 1451 | 1413 |
| DTBench | 90.1% | 82.7% |
| Epoch Capabilities Index | 152.01 | 144.21 |
| ForecastBench | 61.4 | 60.5 |
| NYT Connections (extended) | 85.4% | — |
| Chess Puzzles | 24% | — |
| Thematic Generalization | 63.8% | — |
| LMCA | 38.7% | — |

## Math

- Grok 4.20 (Non-Reasoning): 48.0 (#54)
- Grok 4 Fast: 36.1 (#126)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1455 | 1419 |
| FrontierMath (Tiers 1-3) | 44.9% | — |
| FrontierMath Tier 4 | 17.1% | — |
| OTIS Mock AIME 2024-2025 | 92.2% | — |
| ProofBench | 14% | — |

## Knowledge

- Grok 4.20 (Non-Reasoning): 52.8 (#54)
- Grok 4 Fast: 31.5 (#211)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1440 | 1411 |
| GPQA Diamond | 89.3% | — |
| SimpleQA Verified | 30.2% | — |
| Vectara Hallucination Rate | — | 19.7% |

## Multimodal

- Grok 4.20 (Non-Reasoning): 33.2 (#88)
- Grok 4 Fast: —

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1263 | — |
| Blueprint-Bench 2 | 0% | — |
| LMArena Document | 1416 | — |

## Multilingual

- Grok 4.20 (Non-Reasoning): 54.7 (#38)
- Grok 4 Fast: 51.5 (#106)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1440 | 1397 |
| LMArena Chinese | 1481 | 1458 |
| LMArena French | 1477 | 1433 |
| LMArena German | 1463 | 1383 |
| LMArena Japanese | 1450 | 1358 |
| LMArena Korean | 1417 | 1359 |
| LMArena Russian | 1457 | 1387 |
| LMArena Spanish | 1442 | 1414 |

## Instruction Following

- Grok 4.20 (Non-Reasoning): 75.0 (#79)
- Grok 4 Fast: 73.4 (#116)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1420 | 1388 |

## Long Context

- Grok 4.20 (Non-Reasoning): 45.4 (#33)
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1436 | 1415 |
| Fiction.LiveBench | — | 94.4% |
| CL-bench | 22.2% | — |
| CL-bench Life | 11.9% | — |

## Writing & Preference

- Grok 4.20 (Non-Reasoning): 65.9 (#42)
- Grok 4 Fast: 60.2 (#96)

| Benchmark | Grok 4.20 (Non-Reasoning) | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1451 | 1407 |
| LMArena Creative Writing | 1439 | 1388 |
| LMArena Multi-Turn | 1456 | 1414 |
| EQ-Bench Creative Writing | 1574 | — |

## FAQ

### Is Grok 4.20 (Non-Reasoning) better than Grok 4 Fast?

Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.5 to 39.0 on the Noometry Index.

### Is Grok 4.20 (Non-Reasoning) or Grok 4 Fast better for coding?

Grok 4.20 (Non-Reasoning) scores higher on coding benchmarks: 41.8 versus 32.3 in the Noometry coding category.

### How many benchmarks do Grok 4.20 (Non-Reasoning) and Grok 4 Fast share?

27 benchmarks have published results for both models. Grok 4.20 (Non-Reasoning) has 46 scored results on Noometry and Grok 4 Fast has 30.