# Claude Fable 5 vs Grok 4 Fast

> Claude Fable 5 is the stronger model overall, scoring 66.8 to 39.4 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-fable-5-vs-grok-4-fast
- Last updated: 2026-10-10
- Shared benchmarks: 26

## Summary

- They share 26 benchmarks with published results for both. Claude Fable 5 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 Claude Fable 5 leads 76.8 to 22.2.
- The biggest single-benchmark swing is ARC-AGI-2: 89.2% for Claude Fable 5 and 5.3% for Grok 4 Fast.

## Snapshot

| | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 66.8 | 39.4 |
| Rank | 5 | 167 |
| Context | 1M | — |
| Input $/M | $10 | — |
| Output $/M | $50 | — |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Fable 5: 70.6 (#4)
- Grok 4 Fast: 32.5 (#271)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena WebDev | 1625 | 1159 |
| WeirdML | 91.9% | 42.9% |
| LMArena Coding | 1519 | 1429 |
| DeepSWE | 69.9% | — |
| FrontierCode | 53.5% | — |
| FrontierSWE | 47% | — |
| SciCode | 61% | — |
| GSO | 78.4% | — |
| MirrorCode | 63.9% | — |
| ALE-Bench | 2,041 | — |

## Agentic & Tool Use

- Claude Fable 5: 54.0 (#2)
- Grok 4 Fast: 29.5 (#86)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| τ²-bench Banking | 39.7% | 15.7% |
| LMArena Search | 1230 | 1171 |
| APEX-Agents | 63.6% | — |
| Remote Labor Index | 16.1% | — |
| Cybench | — | 30% |
| PostTrainBench | 41.8% | — |
| GBAEval | 74.5% | — |
| GDP.pdf | 30% | — |
| Vending-Bench 2 | 5,680 | — |

## Reasoning

- Claude Fable 5: 76.8 (#6)
- Grok 4 Fast: 22.2 (#201)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 89.2% | 5.3% |
| Kagi LLM Benchmark | 91.4% | 66.1% |
| ARC-AGI-1 | 98.5% | 48.5% |
| LMArena Hard Prompts | 1508 | 1412 |
| DTBench | 98.4% | 82.7% |
| Epoch Capabilities Index | 162.06 | 144.2 |
| SimpleBench | 81.9% | — |
| NYT Connections (extended) | 92.7% | — |
| CritPt | 28.6% | — |
| Chess Puzzles | 41% | — |
| EnigmaEval | 39.3% | — |
| EBR-Bench | 39.5% | — |
| Mystery Game Puzzles | 52% | — |
| LMCA | 61.1% | — |
| Surface Evolver Bench | 95% | — |
| Bench to the Future 3 | 0.13 | — |
| ForecastBench | — | 60.5 |

## Math

- Claude Fable 5: 88.5 (#5)
- Grok 4 Fast: 38.9 (#123)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1519 | 1419 |
| FrontierMath (Tiers 1-3) | 87% | — |
| FrontierMath Tier 4 | 90.2% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 95% | — |
| FrontierMath Erdős | 0% | — |

## Knowledge

- Claude Fable 5: 62.2 (#25)
- Grok 4 Fast: 32.0 (#214)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1534 | 1411 |
| GPQA Diamond | 85.9% | — |
| SimpleQA Verified | 70.7% | — |
| Vectara Hallucination Rate | — | 19.7% |

## Multimodal

- Claude Fable 5: 45.3 (#17)
- Grok 4 Fast: —

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1324 | — |
| Blueprint-Bench 2 | 38.6% | — |
| Furniture Assembly | 35.8% | — |
| LMArena Document | 1496 | — |

## Multilingual

- Claude Fable 5: 57.3 (#9)
- Grok 4 Fast: 51.3 (#111)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1481 | 1396 |
| LMArena Chinese | 1543 | 1457 |
| LMArena French | 1505 | 1431 |
| LMArena German | 1486 | 1383 |
| LMArena Japanese | 1506 | 1352 |
| LMArena Korean | 1488 | 1357 |
| LMArena Russian | 1504 | 1389 |
| LMArena Spanish | 1498 | 1415 |

## Instruction Following

- Claude Fable 5: 78.6 (#8)
- Grok 4 Fast: 73.2 (#121)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1502 | 1387 |

## Long Context

- Claude Fable 5: 46.3 (#23)
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1509 | 1415 |
| Fiction.LiveBench | — | 94.4% |

## Writing & Preference

- Claude Fable 5: 75.9 (#5)
- Grok 4 Fast: 60.0 (#102)

| Benchmark | Claude Fable 5 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1491 | 1407 |
| LMArena Creative Writing | 1494 | 1387 |
| LMArena Multi-Turn | 1504 | 1414 |
| EQ-Bench Creative Writing | 1943 | — |
| EQ-Bench 4 | 1340 | — |

## FAQ

### Is Claude Fable 5 better than Grok 4 Fast?

Claude Fable 5 is the stronger model overall, scoring 66.8 to 39.4 on the Noometry Index.

### Is Claude Fable 5 or Grok 4 Fast better for coding?

Claude Fable 5 scores higher on coding benchmarks: 70.6 versus 32.5 in the Noometry coding category.

### How many benchmarks do Claude Fable 5 and Grok 4 Fast share?

26 benchmarks have published results for both models. Claude Fable 5 has 62 scored results on Noometry and Grok 4 Fast has 30.