Model comparison
o1-mini vs Step 3.5 Flash
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 34.0 on the Noometry Index.
Last verified . 17 shared benchmarks.
StepFunSummary
- They share 17 benchmarks with published results for both. o1-mini scores higher in 0 categories and Step 3.5 Flash in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 3.5 Flash leads 22.2 to 8.8.
- Step 3.5 Flash has downloadable open weights; the other is API-only.
Side by side
| o1-mini | Step 3.5 Flash | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 34.0 | 42.3 |
| Released | 2024-09-12 | 2026-01-29 |
| Weights | Proprietary | Open |
| Context window | — | 256K |
| Max output | — | 256K |
| Input $ / M tokens | — | $0.10 |
| Output $ / M tokens | — | $0.30 |
| Results tracked | 39 | 19 |
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Category by category
Coding Step 3.5 Flash leads
o1-mini: 35.5 (#224), Step 3.5 Flash: 42.4 (#105)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Coding | 1362 | 1436 |
| Aider Polyglot | 32.9% | — |
| WeirdML | 36.3% | — |
| LiveBench Coding | 48% | — |
| HumanEval+ | 89% | — |
| MBPP+ | 78.8% | — |
Agentic & Tool Use Not comparable
o1-mini: 24.6 (#118), Step 3.5 Flash: —
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| Cybench | 10% | — |
Reasoning Step 3.5 Flash leads
o1-mini: 8.8 (#346), Step 3.5 Flash: 22.2 (#202)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Hard Prompts | 1333 | 1411 |
| ARC-AGI-2 | 0.8% | — |
| SimpleBench | 18.1% | — |
| NYT Connections (extended) | — | 28.4% |
| ARC-AGI-1 | 14% | — |
| LiveBench Reasoning | 72.3% | — |
| LiveBench Data Analysis | 57.9% | — |
| Epoch Capabilities Index | 135.82 | — |
| LiveBench | 57.8% | — |
Math Step 3.5 Flash leads
o1-mini: 35.4 (#186), Step 3.5 Flash: 42.6 (#84)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Math | 1358 | 1408 |
| MathArena Final-Answer Competitions | — | 66.8% |
| OTIS Mock AIME 2024-2025 | 46.9% | — |
| LiveBench Math | 62% | — |
| MATH Level 5 | 89.2% | — |
| FrontierMath (Feb 2025 set) | 1.7% | — |
Knowledge Step 3.5 Flash leads
o1-mini: 34.9 (#192), Step 3.5 Flash: 39.6 (#132)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | 1316 | 1421 |
| GPQA Diamond | 62.4% | — |
| Confabulations | 18.6% | — |
Multilingual Step 3.5 Flash leads
o1-mini: 43.6 (#182), Step 3.5 Flash: 50.5 (#119)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | 1289 | 1385 |
| LMArena Chinese | 1314 | 1447 |
| LMArena French | 1293 | 1421 |
| LMArena German | 1278 | 1405 |
| LMArena Japanese | 1245 | 1354 |
| LMArena Korean | 1223 | 1352 |
| LMArena Russian | 1283 | 1385 |
| LMArena Spanish | 1303 | 1419 |
Instruction Following Step 3.5 Flash leads
o1-mini: 66.7 (#206), Step 3.5 Flash: 73.1 (#124)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1304 | 1385 |
| LiveBench Instruction Following | 65.4% | — |
Long Context Step 3.5 Flash leads
o1-mini: 40.1 (#161), Step 3.5 Flash: 42.8 (#117)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | 1320 | 1402 |
Writing & Preference Step 3.5 Flash leads
o1-mini: 48.4 (#202), Step 3.5 Flash: 58.8 (#113)
| Benchmark | o1-mini | Step 3.5 Flash |
|---|---|---|
| LMArena Text | 1317 | 1403 |
| LMArena Creative Writing | 1244 | 1357 |
| LMArena Multi-Turn | 1314 | 1405 |
| Short-Story Creative Writing | 64.9% | — |
| LiveBench Language | 40.9% | — |
Frequently asked questions
Is o1-mini better than Step 3.5 Flash?
Step 3.5 Flash is the stronger model overall, scoring 42.3 to 34.0 on the Noometry Index.
Is o1-mini or Step 3.5 Flash better for coding?
Step 3.5 Flash scores higher on coding benchmarks: 42.4 versus 35.5 in the Noometry coding category.
How many benchmarks do o1-mini and Step 3.5 Flash share?
17 benchmarks have published results for both models. o1-mini has 39 scored results on Noometry and Step 3.5 Flash has 19.