Model comparison
GPT-6.1 Sol vs Step 3.5 Flash
Step 3.5 Flash has enough public results to be ranked (#116); GPT-6.1 Sol does not yet, so treat this comparison as directional.
Last verified . 0 shared benchmarks.
StepFunSummary
- The widest gap is in coding, where GPT-6.1 Sol leads 51.4 to 41.7.
- Step 3.5 Flash is cheaper at $0.10 / $0.30 per million input/output tokens, against $2 / $10 for GPT-6.1 Sol.
- GPT-6.1 Sol accepts more context: 1.05M tokens versus 256K.
- Step 3.5 Flash has downloadable open weights; the other is API-only.
Side by side
| GPT-6.1 Sol | Step 3.5 Flash | |
|---|---|---|
| Provider | OpenAI | StepFun |
| Noometry Index | 42.1 | 41.7 |
| Released | 2026-09-29 | 2026-01-29 |
| Weights | Proprietary | Open |
| Context window | 1.05M | 256K |
| Max output | 128K | 256K |
| Input $ / M tokens | $2 | $0.10 |
| Output $ / M tokens | $10 | $0.30 |
| Results tracked | 2 | 19 |
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Category by category
Coding GPT-6.1 Sol leads
GPT-6.1 Sol: 51.4, Step 3.5 Flash: 41.7 (#106)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| DeepSWE | 75.2% | — |
| LMArena Coding | — | 1436 |
Agentic & Tool Use Not comparable
GPT-6.1 Sol: 34.3, Step 3.5 Flash: —
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| GDP.pdf | 32% | — |
Reasoning Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 21.2 (#202)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| NYT Connections (extended) | — | 28.4% |
| LMArena Hard Prompts | — | 1411 |
Math Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 40.6 (#77)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| MathArena Final-Answer Competitions | — | 66.8% |
| LMArena Math | — | 1408 |
Knowledge Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 39.0 (#127)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| LMArena Expert | — | 1422 |
Multilingual Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 50.7 (#115)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| LMArena Non-English | — | 1386 |
| LMArena Chinese | — | 1448 |
| LMArena French | — | 1421 |
| LMArena German | — | 1404 |
| LMArena Japanese | — | 1353 |
| LMArena Korean | — | 1350 |
| LMArena Russian | — | 1385 |
| LMArena Spanish | — | 1419 |
Instruction Following Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 73.3 (#119)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| LMArena Instruction Following | — | 1385 |
Long Context Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 42.8 (#112)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| LMArena Longer Query | — | 1402 |
Writing & Preference Not comparable
GPT-6.1 Sol: —, Step 3.5 Flash: 59.0 (#108)
| Benchmark | GPT-6.1 Sol | Step 3.5 Flash |
|---|---|---|
| LMArena Text | — | 1403 |
| LMArena Creative Writing | — | 1357 |
| LMArena Multi-Turn | — | 1405 |
Frequently asked questions
Is GPT-6.1 Sol better than Step 3.5 Flash?
Step 3.5 Flash has enough public results to be ranked (#116); GPT-6.1 Sol does not yet, so treat this comparison as directional.
Which is cheaper, GPT-6.1 Sol or Step 3.5 Flash?
Step 3.5 Flash is cheaper. It lists at $0.10 per million input tokens and $0.30 per million output tokens; GPT-6.1 Sol lists at $2 and $10.
Is GPT-6.1 Sol or Step 3.5 Flash better for coding?
GPT-6.1 Sol scores higher on coding benchmarks: 51.4 versus 41.7 in the Noometry coding category.
Which has the bigger context window?
GPT-6.1 Sol does, with 1.05M tokens against 256K.
How many benchmarks do GPT-6.1 Sol and Step 3.5 Flash share?
0 benchmarks have published results for both models. GPT-6.1 Sol has 2 scored results on Noometry and Step 3.5 Flash has 19.