Model Comparison
Step 3.5 Flash 2603
vs. Step 5 Preview
Comparing 2 AI models · 0 benchmarks · StepFun
Recommended Pick
StStep 3.5 Flash 26036 metric winsStrongest on: Value, Input price, Output price
Best Value
Step 3.5 Flash 2603
100.0 value score
17.0 reasoning / $0.15/1M
Lowest Price
Step 3.5 Flash 2603
$0.10/1M input price
Best Reasoning
Step 5 Preview
43.7 reasoning score
Blends available reasoning benchmarks
Differences That Matter
Best value
Step 3.5 Flash 2603 has the strongest quality-to-price mix at 100.0 out of 100 value points.
Price gap
Step 3.5 Flash 2603 is 10x cheaper on input tokens than Step 5 Preview.
Speed gap
Step 3.5 Flash 2603 generates about 1.2x as many tokens per second as Step 5 Preview.
Reasoning gap
Step 5 Preview leads Step 3.5 Flash 2603 by 26.7 points on reasoning.
Top-pick rationale
Step 3.5 Flash 2603 wins 6 measurable categories, including Value, Input price, Output price, Blended price.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
Step 3.5 Flash 2603
StepFun
TTFT
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Time
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tok/s
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Tokens
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Cost
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Step 5 Preview
StepFun
TTFT
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Time
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tok/s
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Tokens
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Cost
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Which answer was more useful?
Secure AI Chat made in Europe
Use Claude, ChatGPT, Gemini alongside with EU-Hosted Models like Deepseek, Qwen & Kimi.
EU-hosted inference
Servers in Germany & Finland. Designed to meet strict GDPR and ISO 27001 compliance requirements.
Full Comparison
| Metric | Top Pick St Step 3.5 Flash 2603 | St Step 5 Preview |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $0.10/1M | $1.00/1M |
| Output Cost | $0.30/1M | $2.70/1M |
| Blended (3:1) | $0.15/1M | $1.43/1M |
| Specifications | ||
| Organization | StepFun | StepFun |
| Release Date | Apr 2, 2026 | Sep 18, 2026 |
| Performance & Speed | ||
| Throughput | 106.4 tok/s | 91.5 tok/s |
| TTFT | 3510ms | 3100ms |
| Latency | 22310ms | 24960ms |
| Composite Indices | ||
| Value Score | 100.0 | 27.1 |
| Reasoning Score | 17.0 | 43.7 |
| Intelligence | 17.0 | 43.7 |
Key Takeaways
Step 3.5 Flash 2603 offers the best value at $0.10/1M,making it ideal for high-volume applications and cost-conscious projects.
Step 5 Preview has the strongest reasoning profile with a 43.7 reasoning score,combining the available reasoning-heavy benchmarks.
All models support context windows of ∞+ tokens,suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
Step 3.5 Flash 2603
- Cost-sensitive applications
- High-volume processing
Step 5 Preview
- Complex reasoning tasks
- Research & analysis
