Step 3.7 Flash vs Hy4 preview
Step 3.7 Flash costs 2.0x less per output token than Hy4 preview ($1.15 vs $2.2509 per million). Updated October 21, 2026; no benchmark has tested both models yet.
- Coding
- No data
- Overall
- No data
- Output $/M
- $1.15
- Coding
- 44.3
- Overall
- No data
- Output $/M
- $2.2509
Step 3.7 Flash or Hy4 preview: which to pick
Only Hy4 preview has a coding score, 44.3 on the Vibe Coding Index; Step 3.7 Flash has none, so the two cannot be ranked on coding.
Pick Step 3.7 Flash for output tokens 2.0x cheaper ($1.15 vs $2.2509 per million).
No benchmark has tested both yet. Step 3.7 Flash has results on AA Coding Index, SciCode and Terminal-Bench Hard (Artificial Analysis run); Hy4 preview on LMArena WebDev, Terminal-Bench 4 (Vals AI) and Vibe Code Bench (Vals AI). Compare them on price and context instead.
Which one for your work
Each card is decided by one number both models carry. Where only one has it, the card says so and makes no call.
Coding
Vibe Coding Index, six public coding benchmarks
No call
Only Hy4 preview has a coding score, so no call is made.
One side not measured
Intelligence
AA Intelligence Index
No call
Only Step 3.7 Flash has a AA Intelligence Index result, 19.5.
Directional only
Web design
Design Arena: websites
No call
Only Step 3.7 Flash has a Design Arena: websites result, 1196.
Directional only
General
Vals Index
No call
Only Hy4 preview has a Vals Index result, 53.2%.
Directional only
Long documents
Listed context window
Hy4 preview
Hy4 preview takes 1.05M tokens against 262K.
Listed by OpenRouter
Everyday cost
1K input + 500 output tokens
Step 3.7 Flash
Step 3.7 Flash $0.0008, Hy4 preview $0.0019 per turn.
List prices
At a glance
- Coding index
- Step 3.7 Flash not benchmarked, Hy4 preview 44.3 from 3 benchmarks.
- Widest category
- None yet: no category has been tested on both models.
- Widest single gap
- None yet: no benchmark has tested both models.
- Output price
- Step 3.7 Flash $1.15 against Hy4 preview $2.2509 per million output tokens, 2.0x apart.
- Context window
- Step 3.7 Flash takes 262K tokens, Hy4 preview 1.05M.
Benchmark by benchmark
Every board either model has a result on, a category to a fold; bars are each result on a 0 to 100 scale. Only one model is measured on each, so no row names a leader.
CodingDirectional onlySix of these boards feed the Vibe Coding Index14 boards measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| LMArena WebDev | Not measured | 1631 | Only Hy4 preview measured |
| AA Coding Index | 39.6 | Not measured | Only Step 3.7 Flash measured |
| Terminal-Bench 4 (Vals AI) | Not measured | 8.1% | Only Hy4 preview measured |
| Vibe Code Bench (Vals AI) | Not measured | 77.5% | Only Hy4 preview measured |
| Code migration (Vals AI) | Not measured | 47.4% | Only Hy4 preview measured |
| ProgramBench (Vals AI) | Not measured | 0.0% | Only Hy4 preview measured |
| IOI (Vals AI) | Not measured | 59.3% | Only Hy4 preview measured |
| Terminal-Bench 2.1 (Vals AI) | Not measured | 55.1% | Only Hy4 preview measured |
| CyberBench (Vals AI) | Not measured | 65.4% | Only Hy4 preview measured |
| SciCode | 43.9% | Not measured | Only Step 3.7 Flash measured |
| Terminal-Bench Hard (Artificial Analysis run) | 35.6% | Not measured | Only Step 3.7 Flash measured |
| ALE-Bench | 694.1 | Not measured | Only Step 3.7 Flash measured |
| LMArena WebDev: React | Not measured | 1653 | Only Hy4 preview measured |
| LMArena WebDev: HTML | Not measured | 1620 | Only Hy4 preview measured |
| Neither model has a result on the other 25 boards here | |||
IntelligenceDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| AA Intelligence Index | 19.5 | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 1 board here | |||
Agentic workDirectional onlyPublic boards, shown as published, kept out of the index9 boards measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| SREBench (Vals AI) | Not measured | 2.3% | Only Hy4 preview measured |
| Finance Agent (Vals AI) | Not measured | 55.1% | Only Hy4 preview measured |
| Tax Agent Bench (Vals AI) | Not measured | 32.6% | Only Hy4 preview measured |
| Legal Research Bench (Vals AI) | Not measured | 45.2% | Only Hy4 preview measured |
| Harvey's Legal Agent Benchmark (Vals AI) | Not measured | 8.8% | Only Hy4 preview measured |
| Excel Modeling Benchmark (Vals AI) | Not measured | 58.1% | Only Hy4 preview measured |
| BioMysteryBench (Vals AI) | Not measured | 69.3% | Only Hy4 preview measured |
| Terminal-Bench-Science (Vals AI) | Not measured | 1.4% | Only Hy4 preview measured |
| τ²-Bench Telecom | 98.5% | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 32 boards here | |||
ReasoningDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| GPQA Diamond (Artificial Analysis run) | 80.9% | Not measured | Only Step 3.7 Flash measured |
| Humanity's Last Exam (Artificial Analysis run) | 21.4% | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 20 boards here | |||
MathDirectional onlyPublic boards, shown as published, kept out of the index1 board measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| ProofBench | Not measured | 75.0% | Only Hy4 preview measured |
| Neither model has a result on the other 12 boards here | |||
KnowledgeDirectional onlyPublic boards, shown as published, kept out of the index2 boards measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| LegalBench (Vals AI) | Not measured | 83.8% | Only Hy4 preview measured |
| MedCode (Vals AI) | Not measured | 43.3% | Only Hy4 preview measured |
| Neither model has a result on the other 16 boards here | |||
Web designDirectional onlyPublic boards, shown as published, kept out of the index8 boards measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| Design Arena: websites | 1196 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: UI components | 1179 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: game dev | 1158 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: data viz | 1172 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: 3D | 1129 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: all code categories | 1182 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: SVG | 1085 | Not measured | Only Step 3.7 Flash measured |
| Design Arena: ASCII art | 1152 | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 1 board here | |||
GeneralDirectional onlyPublic boards, shown as published, kept out of the index5 boards measured
| Benchmark | Step 3.7 Flash | Hy4 preview | Leader |
|---|---|---|---|
| Vals Index | Not measured | 53.2% | Only Hy4 preview measured |
| Public Benefits Bench (Vals AI) | Not measured | 68.6% | Only Hy4 preview measured |
| MedScribe (Vals AI) | Not measured | 83.6% | Only Hy4 preview measured |
| IFBench | 67.3% | Not measured | Only Step 3.7 Flash measured |
| Long context reasoning (AA-LCR) | 73.7% | Not measured | Only Step 3.7 Flash measured |
| Neither model has a result on the other 41 boards here | |||
What each workload costs
Three fixed token mixes at each model's listed price, so per-token rates become a bill.
Chat turn
1K input + 500 output tokens
Step 3.7 Flash costs less
Repository review
50K input + 3K output tokens
Step 3.7 Flash costs less
Agent loop
200K input + 10K output tokens
Step 3.7 Flash costs less
Listed OpenRouter rates, without cache or batch discounts. A workload that does not fit a model's context window would need splitting.
Specification differences
The leading value in a row is marked; a row with a missing value names no leader. Our two rows are marked in red.
| Specification | StepFun Step 3.7 Flash | Tencent Hy4 preview |
|---|---|---|
| Maker | StepFun | Tencent |
| Weights | Open weights | Open weights |
| Released | May 28, 2026 | August 28, 2026 |
| Context window | 262K | 1.05M |
| Input $/Mtok | $0.20 | $0.7506 |
| Output $/Mtok | $1.15 | $2.2509 |
| Coding index | Not benchmarked | 44.3 |
| Independent measurements behind it | 0 | 3 |
| Cost per solved task | Not computable | Not computable |
| Source | OpenRouter listing | OpenRouter listing |
Questions
Is Step 3.7 Flash better than Hy4 preview for coding?
Only Hy4 preview has a coding score, 44.3 on the Vibe Coding Index; Step 3.7 Flash has none, so the two cannot be ranked on coding. Pick Step 3.7 Flash for output tokens 2.0x cheaper ($1.15 vs $2.2509 per million).
Which is cheaper, Step 3.7 Flash or Hy4 preview?
Step 3.7 Flash costs $0.20 per million input tokens and $1.15 per million output tokens; Hy4 preview costs $0.7506 and $2.2509. Cost per solved task is known for neither of them.
Which has the bigger context window, Step 3.7 Flash or Hy4 preview?
Hy4 preview, with 1.05M tokens against 262K.
Has any benchmark tested both Step 3.7 Flash and Hy4 preview?
No benchmark has tested both yet. Step 3.7 Flash has results on AA Coding Index, SciCode and Terminal-Bench Hard (Artificial Analysis run); Hy4 preview on LMArena WebDev, Terminal-Bench 4 (Vals AI) and Vibe Code Bench (Vals AI). Compare them on price and context instead. Data as of October 21, 2026.