Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Gemma 4 12B (Reasoning) | Step 3.5 Flash 2603 |
|---|---|---|
| Input ($/M tokens) | $0.1 | $0.1 |
| Output ($/M tokens) | $0.3 | $0.3 |
Verdict. Gemma 4 12B (Reasoning) and Step 3.5 Flash 2603 split the benchmark comparison evenly at 1–1. The tiebreaker here is price, speed, and what you actually run them on.
Pricing. Both models sit in the budget bracket for output-token pricing. At 1.0× the per-million-token cost, Step 3.5 Flash 2603 is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). Step 3.5 Flash 2603 makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. Gemma 4 12B (Reasoning) is strongest on Coding Index (31.0), Intelligence Index (22.2). Step 3.5 Flash 2603 leads on Intelligence Index (26.5).
Speed. On throughput, Step 3.5 Flash 2603 generates tokens at 205 tok/s versus 109 tok/s — about 47% faster. On time-to-first-token, Step 3.5 Flash 2603 responds in 1060ms vs 2350ms, which matters most for chat-style UIs.
Provider. Google and StepFun sell to overlapping but distinct developer audiences: Google tends to ship frontier reasoning models with premium positioning, while StepFun often prices more aggressively. Your existing vendor relationships, billing, and SLA preferences may matter as much as the raw numbers above.
Workload cost. Workload scenarios (per million requests at 30M input + 15M output tokens): Gemma 4 12B (Reasoning) costs $7.50 ($90/year); Step 3.5 Flash 2603 costs $7.50 ($90/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): Gemma 4 12B (Reasoning) ≈ $1.10/run, Step 3.5 Flash 2603 ≈ $1.10/run. At agent/realtime scale (200M input / 100M output per million requests): Gemma 4 12B (Reasoning) ≈ $50/run, Step 3.5 Flash 2603 ≈ $50/run.
Recommendation. Both models have legitimate use cases — the right answer depends on whether you are optimizing for benchmark ceiling, latency, or unit cost. Start with the cheaper / faster model, evaluate against your specific task, and only switch if the upgrade shows a meaningful lift.
Head-to-head deltas
Data from Artificial Analysis API — 12 benchmarks
Both models have similar pricing. Check the detailed breakdown above for input vs output token costs.
It's a tie — both models win 1 benchmarks each across 12 evaluated categories. See the detailed benchmark chart above for per-category results.
Step 3.5 Flash 2603 generates tokens faster at 205 tok/s vs 109 tok/s. However, Step 3.5 Flash 2603 has lower time-to-first-token (1.06s vs 2.35s).
Choose based on your priorities: both are similarly priced, both perform similarly on benchmarks, and Step 3.5 Flash 2603 for faster generation. For latency-sensitive apps, check the TTFT comparison above.