Model comparison
Step 3.5 Flash vs Yi-Lightning
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 37.1 on the Noometry Index.
Last verified . 17 shared benchmarks.
StepFunSummary
- 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 42.4 to 27.4.
- Step 3.5 Flash has downloadable open weights; the other is API-only.
Side by side
| Step 3.5 Flash | Yi-Lightning | |
|---|---|---|
| Provider | StepFun | 01.AI |
| Noometry Index | 42.3 | 37.1 |
| Released | 2026-01-29 | 2024-12-02 |
| Weights | Open | Proprietary |
| Context window | 256K | — |
| Max output | 256K | — |
| Input $ / M tokens | $0.10 | — |
| Output $ / M tokens | $0.30 | — |
| Results tracked | 19 | 18 |
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Category by category
Coding Step 3.5 Flash leads
Step 3.5 Flash: 42.4 (#105), Yi-Lightning: 27.4 (#320)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Coding | 1436 | 1312 |
| Aider Polyglot | — | 12.9% |
Reasoning Yi-Lightning leads
Step 3.5 Flash: 22.2 (#202), Yi-Lightning: 25.9 (#139)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Hard Prompts | 1411 | 1302 |
| NYT Connections (extended) | 28.4% | — |
Math Step 3.5 Flash leads
Step 3.5 Flash: 42.6 (#84), Yi-Lightning: 36.2 (#172)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Math | 1408 | 1300 |
| MathArena Final-Answer Competitions | 66.8% | — |
Knowledge Step 3.5 Flash leads
Step 3.5 Flash: 39.6 (#132), Yi-Lightning: 35.4 (#185)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Expert | 1421 | 1286 |
Multilingual Step 3.5 Flash leads
Step 3.5 Flash: 50.5 (#119), Yi-Lightning: 42.2 (#196)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Non-English | 1385 | 1269 |
| LMArena Chinese | 1447 | 1320 |
| LMArena French | 1421 | 1305 |
| LMArena German | 1405 | 1267 |
| LMArena Japanese | 1354 | 1228 |
| LMArena Korean | 1352 | 1192 |
| LMArena Russian | 1385 | 1255 |
| LMArena Spanish | 1419 | 1315 |
Instruction Following Step 3.5 Flash leads
Step 3.5 Flash: 73.1 (#124), Yi-Lightning: 67.4 (#196)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Instruction Following | 1385 | 1278 |
Long Context Step 3.5 Flash leads
Step 3.5 Flash: 42.8 (#117), Yi-Lightning: 39.4 (#181)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Longer Query | 1402 | 1297 |
Writing & Preference Step 3.5 Flash leads
Step 3.5 Flash: 58.8 (#113), Yi-Lightning: 50.2 (#184)
| Benchmark | Step 3.5 Flash | Yi-Lightning |
|---|---|---|
| LMArena Text | 1403 | 1302 |
| LMArena Creative Writing | 1357 | 1280 |
| LMArena Multi-Turn | 1405 | 1311 |
Frequently asked questions
Is Step 3.5 Flash better than Yi-Lightning?
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 37.1 on the Noometry Index.
Is Step 3.5 Flash or Yi-Lightning better for coding?
Step 3.5 Flash scores higher on coding benchmarks: 42.4 versus 27.4 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.