Model Comparison
Solar Pro 2 (Reasoning)
vs. Step 3.5 Flash 2603
Comparing 2 AI models · 0 benchmarks · Upstage, StepFun
Lowest Price
Step 3.5 Flash 2603
$0.10/1M input price
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
Solar Pro 2 (Reasoning)
Upstage
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Step 3.5 Flash 2603
StepFun
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Secure AI Chat made in Europe
Chat with EU-Hosted Models like Deepseek, Qwen & Kimi: open-weight, transparent, no lock-in.
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 | Up Solar Pro 2 (Reasoning) | St Step 3.5 Flash 2603 |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | — | $0.10/1M |
| Output Cost | — | $0.30/1M |
| Blended (3:1) | — | $0.15/1M |
| Specifications | ||
| Organization | Upstage | StepFun |
| Release Date | Jul 9, 2025 | Apr 2, 2026 |
| Performance & Speed | ||
| Throughput | — | 150.1 tok/s |
| TTFT | — | 3270ms |
| Latency | — | 16600ms |
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.
All models support context windows of ∞+ tokens,suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
Solar Pro 2 (Reasoning)
- General-purpose AI
- Versatile applications
Step 3.5 Flash 2603
- Cost-sensitive applications
- High-volume processing
Recommended Comparisons
Popular alternatives
