Model Comparison
Solar Pro 3
vs. Step 3.5 Flash
Comparing 2 AI models · 7 benchmarks · Upstage, StepFun
Recommended Pick
StStep 3.5 Flash9 metric winsStrongest on: Throughput, Reasoning, Intelligence
Lowest Price
Solar Pro 3
$0.00/1M input price
Best Reasoning
Step 3.5 Flash
42.6 reasoning score
Blends available reasoning benchmarks
Best for Coding
Solar Pro 3
16.2 coding index
Composite Indices
Higher is better; speed and price are normalized
Standard Benchmarks
Only benchmarks with data are shown
Differences That Matter
Price gap
Solar Pro 3 is ∞x cheaper on input tokens than Step 3.5 Flash.
Reasoning gap
Step 3.5 Flash leads Solar Pro 3 by 10.4 points on reasoning.
Top-pick rationale
Step 3.5 Flash wins 9 measurable categories, including Throughput, Reasoning, Intelligence, GPQA.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
Solar Pro 3
Upstage
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Step 3.5 Flash
StepFun
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Chat with leading AI models
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 | Up Solar Pro 3 | Top Pick St Step 3.5 Flash |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $0.00/1M | $0.10/1M |
| Output Cost | $0.00/1M | $0.30/1M |
| Blended (3:1) | — | $0.15/1M |
| Specifications | ||
| Organization | Upstage | StepFun |
| Release Date | Apr 6, 2026 | Feb 2, 2026 |
| Performance & Speed | ||
| Throughput | — | 202.4 tok/s |
| TTFT | — | 788ms |
| Latency | — | 10671ms |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | 32.2 | 42.6 |
| Intelligence | 14.1 | 25.5 |
| Coding | 16.2 | — |
| Standard Benchmarks | ||
| GPQA | 72.4% | 83.1% |
| HLE | 10.1% | 19.1% |
| SciCode | 24.7% | 40.4% |
| LCR | 27.0% | 43.0% |
| IFBench | 71.2% | 64.6% |
| TAU-bench v2 | 86.3% | 94.4% |
| TerminalBench Hard | 7.6% | 27.3% |
Key Takeaways
Solar Pro 3 offers the best value at $0.00/1M,making it ideal for high-volume applications and cost-conscious projects.
Step 3.5 Flash has the strongest reasoning profile with a 42.6 reasoning score,combining the available reasoning-heavy benchmarks.
Solar Pro 3 reaches a 16.2 coding index,making it the top choice for software development and code generation tasks.
All models support context windows of ∞+ tokens,suitable for processing lengthy documents and maintaining extended conversations.
When to Choose Each Model
Solar Pro 3
- Cost-sensitive applications
- High-volume processing
- Code generation
- Software development
Step 3.5 Flash
- Complex reasoning tasks
- Research & analysis
