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-5.5 | xAI: Grok 4.3 |
|---|---|---|
| Intelligence Index | 56.7✓ | 53.2 |
| Coding Index | 56.2✓ | 41.0 |
| GPQA Diamond | 93%✓ | 90% |
| Design Arena Elo | 1354✓ | 1255 |
| Speed (tokens/sec) | 29 | 102✓ |
| Latency | 2.8s | 721ms✓ |
| Input price /M | $5.00 | $1.25✓ |
| Output price /M | $30.00 | $2.50✓ |
| Context window | 1.1M✓ | 1M |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSONVision |