Model comparison
Step 5 Preview vs Yi-1.5-34B
Step 5 Preview is the stronger model overall, scoring 47.9 to 30.6 on the Noometry Index.
Last verified . 13 shared benchmarks.
StepFunSummary
- They share 13 benchmarks with published results for both. Step 5 Preview scores higher in 8 categories and Yi-1.5-34B in 0 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Step 5 Preview leads 41.2 to 14.8.
- Yi-1.5-34B has downloadable open weights; the other is API-only.
Side by side
| Step 5 Preview | Yi-1.5-34B | |
|---|---|---|
| Provider | StepFun | 01.AI |
| Noometry Index | 47.9 | 30.6 |
| Released | 2026-09-16 | 2024-05-13 |
| Weights | Proprietary | Open |
| Context window | 1.02M | — |
| Max output | 66K | — |
| Input $ / M tokens | $1 | — |
| Output $ / M tokens | $2.70 | — |
| Results tracked | 18 | 21 |
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Category by category
Coding Step 5 Preview leads
Step 5 Preview: 51.8 (#36), Yi-1.5-34B: 32.4 (#272)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Coding | 1480 | 1169 |
| LMArena WebDev | 1564 | — |
| SciCode | 58.9% | — |
| BigCodeBench Instruct | — | 33.9% |
| BigCodeBench Complete | — | 43.8% |
Reasoning Step 5 Preview leads
Step 5 Preview: 40.0 (#57), Yi-1.5-34B: 22.5 (#191)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Hard Prompts | 1465 | 1160 |
| CritPt | 20.9% | — |
Math Step 5 Preview leads
Step 5 Preview: 46.1 (#72), Yi-1.5-34B: 27.5 (#249)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Math | 1470 | 1182 |
| ProofBench | 42% | — |
| MATH Level 5 | — | 25.5% |
Knowledge Step 5 Preview leads
Step 5 Preview: 41.2 (#112), Yi-1.5-34B: 14.8 (#295)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Expert | 1470 | 1144 |
| GPQA Diamond | — | 32% |
Multimodal Not comparable
Step 5 Preview: 41.0 (#41), Yi-1.5-34B: —
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Vision | 1267 | — |
Multilingual Step 5 Preview leads
Step 5 Preview: 53.8 (#54), Yi-1.5-34B: 32.3 (#256)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Non-English | 1432 | 1121 |
| LMArena Chinese | 1519 | 1213 |
| LMArena Russian | 1436 | 1091 |
| LMArena Spanish | 1439 | 1121 |
| LMArena French | — | 1156 |
| LMArena German | — | 1111 |
| LMArena Japanese | — | 1021 |
| LMArena Korean | — | 1005 |
Instruction Following Step 5 Preview leads
Step 5 Preview: 76.0 (#50), Yi-1.5-34B: 59.2 (#257)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Instruction Following | 1444 | 1139 |
Long Context Step 5 Preview leads
Step 5 Preview: 44.5 (#64), Yi-1.5-34B: 34.6 (#248)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Longer Query | 1455 | 1143 |
Writing & Preference Step 5 Preview leads
Step 5 Preview: 62.8 (#71), Yi-1.5-34B: 37.4 (#257)
| Benchmark | Step 5 Preview | Yi-1.5-34B |
|---|---|---|
| LMArena Text | 1442 | 1173 |
| LMArena Creative Writing | 1410 | 1135 |
| LMArena Multi-Turn | 1447 | 1153 |
Frequently asked questions
Is Step 5 Preview better than Yi-1.5-34B?
Step 5 Preview is the stronger model overall, scoring 47.9 to 30.6 on the Noometry Index.
Is Step 5 Preview or Yi-1.5-34B better for coding?
Step 5 Preview scores higher on coding benchmarks: 51.8 versus 32.4 in the Noometry coding category.
How many benchmarks do Step 5 Preview and Yi-1.5-34B share?
13 benchmarks have published results for both models. Step 5 Preview has 18 scored results on Noometry and Yi-1.5-34B has 21.