Google: Gemini 3.5 Flash wins on more metrics (7 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | Google: Gemini 3.5 Flash | OpenAI: GPT-5.1-Codex |
|---|---|---|
| Intelligence Index | 43.3✓ | 43.1 |
| Coding Index | 47.1✓ | 36.6 |
| GPQA Diamond | 83% | 86%✓ |
| Design Arena Elo | 1328✓ | 1218 |
| Speed (tokens/sec) | 174✓ | 83 |
| Latency | 1.6s✓ | 2.6s |
| Input price /M | $1.50 | $1.25✓ |
| Output price /M | $9.00✓ | $10.00 |
| Context window | 1.0M✓ | 400K |
| Capabilities | ReasoningToolsJSONVisionAudio | ReasoningToolsJSONVision |