Model Comparison
Sonar Reasoning Pro
vs. Step 3.7 Flash
Comparing 2 AI models · 9 benchmarks · Perplexity, StepFun
Recommended Pick
Pe Sonar Reasoning Pro 5 metric wins Strongest on: Input price, Output price, TTFT
Lowest Price
Sonar Reasoning Pro
$0.00/1M input price
Best Reasoning
Sonar Reasoning Pro
66.4 reasoning score
Blends available reasoning benchmarks
Best for Coding
Step 3.7 Flash
37.1 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
Sonar Reasoning Pro is ∞x cheaper on input tokens than Step 3.7 Flash.
Reasoning gap
Sonar Reasoning Pro leads Step 3.7 Flash by 18.6 points on reasoning.
Top-pick rationale
Sonar Reasoning Pro wins 5 measurable categories, including Input price, Output price, TTFT, Latency.
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
—
Time
—
tok/s
—
Tokens
—
Cost
—
Step 3.7 Flash
StepFun
TTFT
—
Time
—
tok/s
—
Tokens
—
Cost
—
Which answer was more useful?
Full Comparison
| Metric | Top Pick Pe Sonar Reasoning Pro | St Step 3.7 Flash |
|---|---|---|
| Pricing per 1M tokens | ||
| Input Cost | $0.00/1M | $0.20/1M |
| Output Cost | $0.00/1M | $1.15/1M |
| Blended (3:1) | — | $0.44/1M |
| Specifications | ||
| Organization | Perplexity | StepFun |
| Release Date | Jan 28, 2025 | May 29, 2026 |
| Performance & Speed | ||
| Throughput | — | 365.0 tok/s |
| TTFT | — | 784ms |
| Latency | — | 6263ms |
| Composite Indices | ||
| Value Score | — | 100.0 |
| Reasoning Score | 66.4 | 47.8 |
| Intelligence | 24.6 | 42.6 |
| Coding | — | 37.1 |
| Standard Benchmarks | ||
| GPQA | — | 80.9% |
| HLE | — | 19.9% |
| MATH 500 | 95.7% | — |
| AIME (Original) | 79.0% | — |
| SciCode | — | 40.0% |
| LCR | — | 63.7% |
| IFBench | — | 67.3% |
| TAU-bench v2 | — | 98.5% |
| TerminalBench Hard | — | 35.6% |
Key Takeaways
Sonar Reasoning Pro offers the best value at $0.00/1M, making it ideal for high-volume applications and cost-conscious projects.
Sonar Reasoning Pro has the strongest reasoning profile with a 66.4 reasoning score, combining the available reasoning-heavy benchmarks.
Step 3.7 Flash reaches a 37.1 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
Sonar Reasoning Pro
- Cost-sensitive applications
- High-volume processing
- Complex reasoning tasks
- Research & analysis
Step 3.7 Flash
- Code generation
- Software development
