OpenAI: GPT-5.5 wins on more metrics (8 of 8), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-5.4 Pro | OpenAI: GPT-5.5 |
|---|---|---|
| Intelligence Index | — | 56.7✓ |
| Coding Index | — | 56.2✓ |
| GPQA Diamond | — | 93%✓ |
| Design Arena Elo | — | 1354✓ |
| Speed (tokens/sec) | 4 | 36✓ |
| Latency | 25.3s | 3.8s✓ |
| Input price /M | $30.00 | $5.00✓ |
| Output price /M | $180.00 | $30.00✓ |
| Context window | 1.1M | 1.1M |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSONVision |