OpenAI: GPT-5.6 Luna vs xAI: Grok 4.5
xAI: Grok 4.5 wins on more metrics (5 of 7), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-5.6 Luna | xAI: Grok 4.5 |
|---|---|---|
| Intelligence Index | 51.2 | 53.8✓ |
| Coding Index | 71.4 | 72.4✓ |
| GPQA Diamond | 91% | 93%✓ |
| Design Arena Elo | — | — |
| Speed (tokens/sec) | 60 | 71✓ |
| Latency | 1.7s | 1.3s✓ |
| Input price /M | $1.00✓ | $2.00 |
| Output price /M | $6.00 | $6.00 |
| Context window | 1.1M✓ | 500K |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSONVision |