OpenAI: GPT-5.4 Nano wins on more metrics (5 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-5.4 Nano | Z.ai: GLM 5.1 |
|---|---|---|
| Intelligence Index | 44.0✓ | 43.8 |
| Coding Index | 43.9✓ | 35.8 |
| GPQA Diamond | 82% | 84%✓ |
| Design Arena Elo | — | 1366✓ |
| Speed (tokens/sec) | 66 | 84✓ |
| Latency | 570ms | 475ms✓ |
| Input price /M | $0.200✓ | $0.980 |
| Output price /M | $1.25✓ | $3.08 |
| Context window | 400K✓ | 203K |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSON |