OpenAI: GPT-5.5 wins on more metrics (5 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-4o | OpenAI: GPT-5.5 |
|---|---|---|
| Intelligence Index | — | 56.7✓ |
| Coding Index | — | 56.2✓ |
| GPQA Diamond | — | 93%✓ |
| Design Arena Elo | 975 | 1354✓ |
| Speed (tokens/sec) | 44✓ | 37 |
| Latency | 463ms✓ | 4.0s |
| Input price /M | $2.50✓ | $5.00 |
| Output price /M | $10.00✓ | $30.00 |
| Context window | 128K | 1.1M✓ |
| Capabilities | ToolsJSONVision | ReasoningToolsJSONVision |