R1 vs Step 3.5 Flash
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for R1 and Step 3.5 Flash.
R1
DeepSeek R1 is here: Performance on par with [OpenAI o1](/openai/o1), but open-sourced and with fully open reasoning tokens. It's 671B parameters in size, with 37B active in an inference pass....
Step 3.5 Flash
Step 3.5 Flash is StepFun's most capable open-source foundation model. Built on a sparse Mixture of Experts (MoE) architecture, it selectively activates only 11B of its 196B parameters per token....
Technical Specifications
| Specification | R1 | Step 3.5 Flash |
|---|---|---|
| Provider | DeepSeek | StepFun |
| Context Window | 163,840 tokens | 262,144 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | self hostable | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-01-20 | 2026-01-29 |
API Pricing Comparison
Input Price per Million Tokens
R1
$0.70
Step 3.5 Flash
$0.10
Output Price per Million Tokens
R1
$2.50
Step 3.5 Flash
$0.30
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
R1 Quirks & Gotchas
No developer gotchas reported.
Step 3.5 Flash Quirks & Gotchas
No developer gotchas reported.