Model Comparison
Sonar Reasoning Pro
vs. Step 3.5 Flash 2603
Sonar Reasoning Pro has not been available at LLMBase since 26 October 2026. See all open-weight models →
Comparing 2 AI models · 0 benchmarks · Perplexity, 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.
Sonar Reasoning Pro
Perplexity
TTFT
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Time
—
tok/s
—
Tokens
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Cost
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Step 3.5 Flash 2603
StepFun
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
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Full Comparison
| Metric | Pe Sonar Reasoning Pro | 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 | Perplexity | StepFun |
| Release Date | Jan 28, 2025 | Apr 2, 2026 |
| Performance & Speed | ||
| Throughput | — | 150.1 tok/s |
| TTFT | — | 3260ms |
| Latency | — | 16590ms |
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
Sonar Reasoning Pro
- General-purpose AI
- Versatile applications
Step 3.5 Flash 2603
- Cost-sensitive applications
- High-volume processing
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