OpenAI: GPT-5.2-Codex vs Z.ai: GLM 5.1
Z.ai: GLM 5.1 wins on more metrics (6 of 8), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-5.2-Codex | Z.ai: GLM 5.1 |
|---|---|---|
| Intelligence Index | 40.1 | 40.2✓ |
| Coding Index | — | 55.8✓ |
| GPQA Diamond | 90%✓ | 87% |
| Design Arena Elo | — | — |
| Speed (tokens/sec) | 76 | 119✓ |
| Latency | 2.2s | 365ms✓ |
| Input price /M | $1.75 | $0.966✓ |
| Output price /M | $14.00 | $3.04✓ |
| Context window | 400K✓ | 203K |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSON |