# Step 3.5 Flash vs Yi-Lightning

> Step 3.5 Flash is the stronger model overall, scoring 41.7 to 36.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/step-3-5-flash-vs-yi-lightning
- Last updated: 2026-10-10
- Shared benchmarks: 17

## Summary

- They share 17 benchmarks with published results for both. Step 3.5 Flash scores higher in 7 categories and Yi-Lightning in 1 category; 8 gaps are clear of the uncertainty.
- The widest gap is in coding, where Step 3.5 Flash leads 41.7 to 27.0.
- Step 3.5 Flash has downloadable open weights; the other is API-only.

## Snapshot

| | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| Provider | StepFun | 01.AI |
| Noometry Index | 41.7 | 36.5 |
| Rank | 116 | 206 |
| Context | 256K | — |
| Input $/M | $0.10 | — |
| Output $/M | $0.30 | — |
| Weights | Open | Proprietary |

## Coding

- Step 3.5 Flash: 41.7 (#106)
- Yi-Lightning: 27.0 (#315)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Coding | 1436 | 1313 |
| Aider Polyglot | — | 12.9% |

## Reasoning

- Step 3.5 Flash: 21.2 (#202)
- Yi-Lightning: 24.9 (#137)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Hard Prompts | 1411 | 1302 |
| NYT Connections (extended) | 28.4% | — |

## Math

- Step 3.5 Flash: 40.6 (#77)
- Yi-Lightning: 33.5 (#173)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Math | 1408 | 1300 |
| MathArena Final-Answer Competitions | 66.8% | — |

## Knowledge

- Step 3.5 Flash: 39.0 (#127)
- Yi-Lightning: 34.8 (#182)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Expert | 1422 | 1286 |

## Multilingual

- Step 3.5 Flash: 50.7 (#115)
- Yi-Lightning: 42.4 (#191)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Non-English | 1386 | 1269 |
| LMArena Chinese | 1448 | 1320 |
| LMArena French | 1421 | 1304 |
| LMArena German | 1404 | 1267 |
| LMArena Japanese | 1353 | 1228 |
| LMArena Korean | 1350 | 1192 |
| LMArena Russian | 1385 | 1255 |
| LMArena Spanish | 1419 | 1315 |

## Instruction Following

- Step 3.5 Flash: 73.3 (#119)
- Yi-Lightning: 67.6 (#191)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Instruction Following | 1385 | 1278 |

## Long Context

- Step 3.5 Flash: 42.8 (#112)
- Yi-Lightning: 39.4 (#176)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Longer Query | 1402 | 1297 |

## Writing & Preference

- Step 3.5 Flash: 59.0 (#108)
- Yi-Lightning: 50.4 (#178)

| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Text | 1403 | 1302 |
| LMArena Creative Writing | 1357 | 1280 |
| LMArena Multi-Turn | 1405 | 1311 |

## FAQ

### Is Step 3.5 Flash better than Yi-Lightning?

Step 3.5 Flash is the stronger model overall, scoring 41.7 to 36.5 on the Noometry Index.

### Is Step 3.5 Flash or Yi-Lightning better for coding?

Step 3.5 Flash scores higher on coding benchmarks: 41.7 versus 27.0 in the Noometry coding category.

### How many benchmarks do Step 3.5 Flash and Yi-Lightning share?

17 benchmarks have published results for both models. Step 3.5 Flash has 19 scored results on Noometry and Yi-Lightning has 18.