StepFun: Step 3.5 Flash wins on more metrics (5 of 8), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | MoonshotAI: Kimi K2.5 | StepFun: Step 3.5 Flash |
|---|---|---|
| Intelligence Index | 37.3 | 37.8✓ |
| Coding Index | 25.8 | 31.6✓ |
| GPQA Diamond | 79% | 83%✓ |
| Design Arena Elo | 1293✓ | — |
| Speed (tokens/sec) | 89✓ | 47 |
| Latency | 211ms✓ | 403ms |
| Input price /M | $0.375 | $0.090✓ |
| Output price /M | $2.02 | $0.300✓ |
| Context window | 262K | 262K |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSON |