Compare · ModelsLive · 2 picked · head to head
DeepSeek V4 Pro vs Step 3.5 Flash
Side by side · benchmarks, pricing, and signals you can act on.
Winner summary
DeepSeek V4 Pro wins on 3/4 benchmarks
DeepSeek V4 Pro wins 3 of 4 shared benchmarks. Leads in speed · arena.
Category leads
speed·DeepSeek V4 Proarena·DeepSeek V4 Pro
Hype vs Reality
Attention vs performance
DeepSeek V4 Pro
#13 by perf·no signal
Step 3.5 Flash
#9 by perf·#11 by attention
Best value
Step 3.5 Flash
3.4x better value than DeepSeek V4 Pro
DeepSeek V4 Pro
112.8 pts/$
$0.65/M
Step 3.5 Flash
384.5 pts/$
$0.20/M
Vendor risk
Mixed exposure
One or more vendors flagged
DeepSeek
$3.4B·Tier 1
StepFun
$5.0B·Tier 1
Head to head
4 benchmarks · 2 models
DeepSeek V4 ProStep 3.5 Flash
Artificial Analysis · Agentic Index
Step 3.5 Flash leads by +15.6
Artificial Analysis Agentic Index · a composite score measuring how well a model performs in agentic workflows · multi-step tool use, planning, error recovery, and autonomous task completion. Aggregates results from multiple agentic benchmarks including SWE-bench, tool-use tests, and planning evaluations. The canonical single-number metric for "how good is this model as an agent?"
DeepSeek V4 Pro
36.4
Step 3.5 Flash
52.0
Artificial Analysis · Coding Index
DeepSeek V4 Pro leads by +27.7
Artificial Analysis Coding Index · a composite score that aggregates performance across multiple coding benchmarks into a single index. Tracks code generation quality, debugging ability, multi-language competence, and real-world software engineering tasks. Used by Artificial Analysis to rank model coding capability in a normalized, comparable format. Useful for developers choosing between models for coding-heavy workloads.
DeepSeek V4 Pro
59.4
Step 3.5 Flash
31.6
Artificial Analysis · Quality Index
DeepSeek V4 Pro leads by +6.5
DeepSeek V4 Pro
44.3
Step 3.5 Flash
37.8
Chatbot Arena Elo · Overall
DeepSeek V4 Pro leads by +60.8
DeepSeek V4 Pro
1455.9
Step 3.5 Flash
1395.2
Full benchmark table
| Benchmark | DeepSeek V4 Pro | Step 3.5 Flash |
|---|---|---|
Artificial Analysis · Agentic Index Artificial Analysis Agentic Index · a composite score measuring how well a model performs in agentic workflows · multi-step tool use, planning, error recovery, and autonomous task completion. Aggregates results from multiple agentic benchmarks including SWE-bench, tool-use tests, and planning evaluations. The canonical single-number metric for "how good is this model as an agent?" | 36.4 | 52.0 |
Artificial Analysis · Coding Index Artificial Analysis Coding Index · a composite score that aggregates performance across multiple coding benchmarks into a single index. Tracks code generation quality, debugging ability, multi-language competence, and real-world software engineering tasks. Used by Artificial Analysis to rank model coding capability in a normalized, comparable format. Useful for developers choosing between models for coding-heavy workloads. | 59.4 | 31.6 |
Artificial Analysis · Quality Index | 44.3 | 37.8 |
Chatbot Arena Elo · Overall | 1455.9 | 1395.2 |
Pricing · per 1M tokens · projected $/mo at 10M tokens
| Model | Input | Output | Context | Projected $/mo |
|---|---|---|---|---|
| $0.43 | $0.87 | 1.0M tokens (~524 books) | $5.44 | |
| $0.10 | $0.30 | 262K tokens (~131 books) | $1.50 |