Model Comparison
Sonar Reasoning Pro
vs. Step 3.5 Flash
Comparing 2 AI models · 0 benchmarks · Perplexity, 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
26.0 reasoning score
Blends available reasoning benchmarks
Differences That Matter
Reasoning gap
Step 3.5 Flash leads Sonar Reasoning Pro by 8.0 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.
Sonar Reasoning Pro
Perplexity
TTFT
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Time
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tok/s
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Tokens
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Cost
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Step 3.5 Flash
StepFun
TTFT
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Time
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tok/s
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Tokens
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Cost
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Which answer was more useful?
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Full Comparison
| Metric | Pe Sonar Reasoning Pro | 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 | Perplexity | StepFun |
| Release Date | Jan 28, 2025 | Feb 2, 2026 |
| Performance & Speed | ||
| Throughput | — | 214.0 tok/s |
| TTFT | — | 1050ms |
| Latency | — | 10400ms |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | 18.0 | 26.0 |
| Intelligence | 18.0 | 26.0 |
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 26.0 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
Sonar Reasoning Pro
- General-purpose AI
- Versatile applications
Step 3.5 Flash
- Cost-sensitive applications
- High-volume processing
- Complex reasoning tasks
- Research & analysis
