Model Comparison
GPT-4o (ChatGPT)
vs. Step 3.5 Flash
Comparing 2 AI models · 0 benchmarks · OpenAI, StepFun
Recommended Pick
StStep 3.5 Flash2 metric winsStrongest on: Reasoning, Intelligence
Lowest Price
Step 3.5 Flash
$0.10/1M input price
Best Reasoning
Step 3.5 Flash
16.6 reasoning score
Blends available reasoning benchmarks
Differences That Matter
Reasoning gap
Step 3.5 Flash leads GPT-4o (ChatGPT) by 9.4 points on reasoning.
Top-pick rationale
Step 3.5 Flash wins 2 measurable categories, including Reasoning, Intelligence.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
GPT-4o (ChatGPT)
OpenAI
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Step 3.5 Flash
StepFun
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Secure AI Chat made in Europe
Use open-weight models like DeepSeek, Qwen and Kimi in one app.
EU-hosted open models, one API
Servers in Germany & Finland. Operated by a German company under the GDPR, DPA available, ISO 27001-certified data centres.
Full Comparison
| Metric | Op GPT-4o (ChatGPT) | Top Pick St Step 3.5 Flash |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | — | $0.10/1M |
| Output Cost | — | $0.30/1M |
| Blended (3:1) | — | $0.15/1M |
| Specifications | ||
| Organization | OpenAI | StepFun |
| Release Date | Feb 15, 2025 | Feb 2, 2026 |
| Performance & Speed | ||
| Throughput | — | 178.5 tok/s |
| TTFT | — | 3300ms |
| Latency | — | 14500ms |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | 7.2 | 16.6 |
| Intelligence | 7.2 | 16.6 |
Key Takeaways
Step 3.5 Flash offers the best value at $0.10/1M,making it ideal for high-volume applications and cost-conscious projects.
Step 3.5 Flash has the strongest reasoning profile with a 16.6 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
GPT-4o (ChatGPT)
- General-purpose AI
- Versatile applications
Step 3.5 Flash
- Cost-sensitive applications
- High-volume processing
- Complex reasoning tasks
- Research & analysis
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