Data points: 86
The readout for DeepSeek V4 Flash and Step 3.5 Flash, before the detailed comparison sheet.
Decision read
DeepSeek V4 Flash
DeepSeek V4 Flash currently has the stronger profile, with verified wins split 5 to 1.
Evidence depth
86 data points
Includes 8 benchmark rows, 1 audit samples, and 7 provider examples.
Selection signal
Start with DeepSeek V4 Flash
The charts below split 16 high-signal samples across speed, scores, and audit health.
Model compare DeepSeek V4 Flash vs Step 3.5 Flashdeepseek-v4-flash-vs-step-3-5-flash | Model A DeepSeek V4 Flash | Model B Step 3.5 Flash |
|---|---|---|
| Overall leader | Leading | Contender |
| Verified metric wins | 5 wins | 1 wins |
| Where it leads | Cheapest input price, First-token latency, Free providers, Provider coverage, Recent tests |
Third-party benchmark profile synced into LMSpeed; only metrics available for both models are shown.
| Metric | DeepSeek V4 Flash | Step 3.5 Flash |
|---|---|---|
| Output price | $0.280/M#4 |
Latest completed audits from shared providers, with four safety and integrity score groups plus report links.
| Provider | DeepSeek V4 Flash | Step 3.5 Flash |
|---|---|---|
Winner: DeepSeek V4 Flash | DeepSeek V4 Flash deepseek-v4-flash Audit score 81 72 |
Speed aggregates and input/output pricing share each provider row for real API selection and migration cost checks.
| Provider | DeepSeek V4 Flash | Step 3.5 Flash |
|---|---|---|
50 tests | DeepSeek V4 Flash speed / latency 24 tok/s / 9354ms input / output No data |
This report only uses LMSpeed data for DeepSeek V4 Flash and Step 3.5 Flash: pricing, speed aggregates, third-party benchmark scores, and shared provider samples.
| Guidance | DeepSeek V4 Flash | Step 3.5 Flash |
|---|---|---|
| When to choose each model | DeepSeek V4 Flash DeepSeek V4 Flash is stronger when you prioritize Cheapest input price, First-token latency, Free providers, Provider coverage, Recent tests. | Step 3.5 Flash Step 3.5 Flash is stronger when you prioritize Average speed. |
TL;DR: DeepSeek V4 Flash leads across 86 verifiable data points, including pricing, speed, latency, benchmarks, and provider examples.
Continue from DeepSeek V4 Flash vs Step 3.5 Flash into nearby model comparisons with enough verified LMSpeed data.
| Average speed |
| Model metadata | DeepSeek V4 Flash exposes 1.0M tokens; notable signals: Text input, Text output, Tool calling, Structured outputs. | Step 3.5 Flash exposes 262.1K tokens; notable signals: Text input, Text output, Tool calling, JSON mode. |
|---|---|---|
| Developer | DeepSeek | No data |
| Context window | 1.0M tokens | 262.1K tokens |
| Max output | 131.1K tokens | 16.4K tokens |
| Released | Apr 2026 | Jan 2026 |
| Modalities | Input Text Output Text | Input Text Output Text |
| Features | Text inputText outputTool callingStructured outputsJSON modeReasoning | Text inputText outputTool callingJSON modeReasoning |
| Parameters | No data | No data |
| Tokenizer | DeepSeek | Other |
| Knowledge cutoff | No data | No data |
| OpenRouter ID | deepseek/deepseek-v4-flash | stepfun/step-3.5-flash |
| References | No data | No data |
| Input price | $0.140/M#8 | $0.100/M#6 |
|---|
| Blended price | $0.175/M#10 | $0.150/M#8 |
|---|
| Output speed | 92.9 tok/s#53 | 215.0 tok/s#9 |
|---|
| GPQA | 89.4%#11 | 82.6%#46 |
|---|
| HLE | 32.1%#13 | 22.6%#34 |
|---|
| SciCode | 44.9%#23 | 38.5%#55 |
|---|
| Time to first token | 0.98 s#37 | 0.85 s#30 |
|---|
Step 3.5 Flash step-3.5-flash-2603 No audit yet |
Step 3.5 Flash
speed / latency
82 tok/s / 4793ms
input / output
No data
OpenRouter45 tests | DeepSeek V4 Flash speed / latency 88 tok/s / 3315ms input / output No data | Step 3.5 Flash speed / latency 100 tok/s / 6815ms input / output No data |
|---|
SiliconFlow30 tests | DeepSeek V4 Flash speed / latency 45 tok/s / 9731ms input / output No data | Step 3.5 Flash speed / latency 84 tok/s / 3375ms input / output No data |
|---|
小水管 API20 tests | DeepSeek V4 Flash sensenova/deepseek-v4-flash speed / latency 83 tok/s / 5114ms input / output $0/M / $0/M | Step 3.5 Flash stepfun/step-3.5-flash speed / latency N/A / N/A input / output $0.071/M / $0.071/M |
|---|
9527 API10 tests | DeepSeek V4 Flash speed / latency 31 tok/s / 7293ms input / output No data | Step 3.5 Flash speed / latency N/A / N/A input / output No data |
|---|
DeepSeek V4 Flash deepseek-v4-flash speed / latency No data input / output $0/M / $0/M | Step 3.5 Flash stepfun-ai/step-3.5-flash speed / latency No data input / output $12.50/M / $15.63/M |
DeepSeek V4 Flash deepseek-ai/deepseek-v4-flash speed / latency No data input / output $0/M / $0/M | Step 3.5 Flash 英伟达/stepfun-ai/step-3.5-flash speed / latency No data input / output $0/M / $0/M |
Rankings are based on community-submitted tests and periodic health probes. Advisory only, not official data.
