OpenAI: GPT-5.5 wins on more metrics (5 of 8), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | Anthropic: Claude Fable 5 | OpenAI: GPT-5.5 |
|---|---|---|
| Intelligence Index | 64.9✓ | 56.7 |
| Coding Index | 62.0✓ | 56.2 |
| GPQA Diamond | 93% | 93% |
| Design Arena Elo | 1417✓ | 1354 |
| Speed (tokens/sec) | — | 36✓ |
| Latency | — | 2.8s✓ |
| Input price /M | $10.00 | $5.00✓ |
| Output price /M | $50.00 | $30.00✓ |
| Context window | 1M | 1.1M✓ |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSONVision |