Z.ai: GLM 5.2 wins on more metrics (6 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-5.5 | Z.ai: GLM 5.2 |
|---|---|---|
| Intelligence Index | 50.4 | 51.1✓ |
| Coding Index | 71.5✓ | 68.8 |
| GPQA Diamond | 93%✓ | 90% |
| Design Arena Elo | 1349 | 1370✓ |
| Speed (tokens/sec) | 43 | 54✓ |
| Latency | 3.2s | 1.4s✓ |
| Input price /M | $5.00 | $1.20✓ |
| Output price /M | $30.00 | $4.10✓ |
| Context window | 1.1M✓ | 1.0M |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSON |