Model Comparison
Solar Open2 250B
vs. Step 3.5 Flash 2603
Comparing 2 AI models · 7 benchmarks · Upstage, StepFun
Recommended Pick
UpSolar Open2 250B8 metric winsStrongest on: Input price, Output price, Reasoning
Lowest Price
Solar Open2 250B
$0.00/1M input price
Best Reasoning
Solar Open2 250B
50.5 reasoning score
Blends available reasoning benchmarks
Best for Coding
Solar Open2 250B
44.7 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 Open2 250B is ∞x cheaper on input tokens than Step 3.5 Flash 2603.
Reasoning gap
Solar Open2 250B leads Step 3.5 Flash 2603 by 6.0 points on reasoning.
Top-pick rationale
Solar Open2 250B wins 8 measurable categories, including Input price, Output price, Reasoning, Intelligence.
Response Face-Off
Run one prompt through the selected models and compare response quality with live speed and cost context.
Solar Open2 250B
Upstage
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Step 3.5 Flash 2603
StepFun
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
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Full Comparison
| Metric | Top Pick Up Solar Open2 250B | St Step 3.5 Flash 2603 |
|---|---|---|
| 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 | Aug 12, 2026 | Apr 2, 2026 |
| Performance & Speed | ||
| Throughput | — | — |
| TTFT | — | — |
| Latency | — | — |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | 50.5 | 44.5 |
| Intelligence | 37.4 | 26.5 |
| Coding | 44.7 | — |
| Standard Benchmarks | ||
| GPQA | 85.7% | 82.6% |
| HLE | 28.5% | 24.5% |
| SciCode | 45.6% | 38.5% |
| LCR | 68.3% | 60.3% |
| IFBench | — | 66.5% |
| TAU-bench v2 | — | 87.4% |
| TerminalBench Hard | — | 32.6% |
Key Takeaways
Solar Open2 250B offers the best value at $0.00/1M,making it ideal for high-volume applications and cost-conscious projects.
Solar Open2 250B has the strongest reasoning profile with a 50.5 reasoning score,combining the available reasoning-heavy benchmarks.
Solar Open2 250B reaches a 44.7 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 Open2 250B
- Cost-sensitive applications
- High-volume processing
- Complex reasoning tasks
- Research & analysis
- Code generation
- Software development
Step 3.5 Flash 2603
- General-purpose AI
- Versatile applications
