Model comparison
DeepSeek-V3.1-Terminus vs Step 5 Preview
Step 5 Preview is the stronger model overall, scoring 43.8 to 42.6 on the Noometry Index. DeepSeek-V3.1-Terminus costs 3.0× less per token, which makes it the better buy when Step 5 Preview's lead doesn't matter for your workload.
Last verified . 2 shared benchmarks.
DeepSeek
StepFunSummary
- They share 2 benchmarks with published results for both. DeepSeek-V3.1-Terminus scores higher in 0 categories and Step 5 Preview in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Step 5 Preview leads 38.0 to 25.7.
- The biggest single-benchmark swing is CritPt: 1.7% for DeepSeek-V3.1-Terminus and 20.9% for Step 5 Preview.
- DeepSeek-V3.1-Terminus is cheaper at $0.30 / $1 per million input/output tokens, against $1 / $2.70 for Step 5 Preview.
- Step 5 Preview accepts more context: 1.02M tokens versus 164K.
- DeepSeek-V3.1-Terminus has downloadable open weights; the other is API-only.
Side by side
| DeepSeek-V3.1-Terminus | Step 5 Preview | |
|---|---|---|
| Provider | DeepSeek | StepFun |
| Noometry Index | 42.6 | 43.8 |
| Released | 2025-09-22 | 2026-09-16 |
| Weights | Open | Proprietary |
| Context window | 164K | 1.02M |
| Max output | 66K | 66K |
| Input $ / M tokens | $0.30 | $1 |
| Output $ / M tokens | $1 | $2.70 |
| Results tracked | 16 | 3 |
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Category by category
Coding Step 5 Preview leads
DeepSeek-V3.1-Terminus: 41.5 (#114), Step 5 Preview: 50.6 (#40)
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| SciCode | 40.6% | 58.9% |
| LMArena WebDev | — | 1569 |
| LMArena Coding | 1426 | — |
| ALE-Bench | 745.17 | — |
Reasoning Step 5 Preview leads
DeepSeek-V3.1-Terminus: 25.7 (#126), Step 5 Preview: 38.0 (#58)
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| CritPt | 1.7% | 20.9% |
| Kagi LLM Benchmark | 57.4% | — |
| LMArena Hard Prompts | 1427 | — |
| DTBench | 81.3% | — |
| LMCA | 28.6% | — |
Math Not comparable
DeepSeek-V3.1-Terminus: 35.7 (#138), Step 5 Preview: —
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| LMArena Math | 1402 | — |
Multilingual Not comparable
DeepSeek-V3.1-Terminus: 52.3 (#87), Step 5 Preview: —
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1407 | — |
| LMArena Russian | 1434 | — |
Instruction Following Not comparable
DeepSeek-V3.1-Terminus: 74.4 (#96), Step 5 Preview: —
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1406 | — |
Long Context Not comparable
DeepSeek-V3.1-Terminus: 43.5 (#88), Step 5 Preview: —
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1426 | — |
Writing & Preference Not comparable
DeepSeek-V3.1-Terminus: 61.3 (#87), Step 5 Preview: —
| Benchmark | DeepSeek-V3.1-Terminus | Step 5 Preview |
|---|---|---|
| LMArena Text | 1420 | — |
| LMArena Creative Writing | 1404 | — |
| LMArena Multi-Turn | 1411 | — |
Frequently asked questions
Is DeepSeek-V3.1-Terminus better than Step 5 Preview?
Step 5 Preview is the stronger model overall, scoring 43.8 to 42.6 on the Noometry Index. DeepSeek-V3.1-Terminus costs 3.0× less per token, which makes it the better buy when Step 5 Preview's lead doesn't matter for your workload.
Which is cheaper, DeepSeek-V3.1-Terminus or Step 5 Preview?
DeepSeek-V3.1-Terminus is cheaper. It lists at $0.30 per million input tokens and $1 per million output tokens; Step 5 Preview lists at $1 and $2.70.
Is DeepSeek-V3.1-Terminus or Step 5 Preview better for coding?
Step 5 Preview scores higher on coding benchmarks: 50.6 versus 41.5 in the Noometry coding category.
Which has the bigger context window?
Step 5 Preview does, with 1.02M tokens against 164K.
How many benchmarks do DeepSeek-V3.1-Terminus and Step 5 Preview share?
2 benchmarks have published results for both models. DeepSeek-V3.1-Terminus has 16 scored results on Noometry and Step 5 Preview has 3.