Claude Fable 5.1 vs GPT-5.4 Pro
Claude Fable 5.1 
GPT-5.4 Pro Verdict
- Claude Fable 5.1 (xhigh) leads on quality: 70.3 vs 64.2.
- Claude Fable 5.1 (xhigh) is stronger in coding, composite, knowledge, long context, reasoning.
- GPT-5.4 Pro is stronger in instruction following, multimodal.
- Claude Fable 5.1 (xhigh) is 3.4× cheaper ($20.00 vs $67.50 per 1M blended).
- Claude Fable 5.1 (xhigh) streams 58.0× faster (58 vs 1 tokens per second).
| Metric | Claude Fable 5.1 (xhigh) | GPT-5.4 Pro |
|---|---|---|
| BenchLeader Index | 70.3 | 64.2 |
| Coding score | 71.3 | – |
| Composite score | 95.0 | – |
| Knowledge score | 84.1 | 73.2 |
| Long context score | 68.1 | – |
| Reasoning score | 76.4 | 75.1 |
| Instruction following score | – | 67.3 |
| Multimodal score | – | 69.8 |
| Blended price $/M | $20.00 | $67.50 |
| Output speed | 58 tok/s | 1 tok/s |
| Time to first answer | 132.0 s | 6.7 s |
| Context window | 1M | 1.1M |
| Humanity's Last Exam | 46.5% | 44.3% |
| SimpleBench | – | 74.1% |
| SciCode | 60.1% | – |
| Epoch Capabilities Index | – | 158.9 |
| AA Intelligence Index | 53.2 | – |
| AA-LCR | 83.0% | – |
| AA-Omniscience | 42.4 | – |
| GPQA Diamond (AA) | 93.4% | – |
| Humanity's Last Exam (AA) | 58.7% | – |
| SciCode (AA) | 60.9% | – |
| MultiChallenge | – | 69.2% |
| VISTA | – | 53.9% |
| MultiNRC | – | 62.3% |
| TutorBench | – | 56.6% |
| ARC-AGI-1 | 96.5% | – |
| ARC-AGI-2 | 90.0% | – |
Data as of 2026-09-09. Best configuration of each model; every score links to its source on the model pages.