Side-by-side comparison of pricing, 12 benchmarks, and generation speed.
| Metric | Grok 3 mini Reasoning (high) | gpt-oss-120b (low) |
|---|---|---|
| Input ($/M tokens) | $0.3 | $0.15 |
| Output ($/M tokens) | $0.5 | $0.54 |
Verdict. Grok 3 mini Reasoning (high) and gpt-oss-120b (low) 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 0.9× the per-million-token cost, Grok 3 mini Reasoning (high) is meaningfully cheaper if your traffic is output-heavy (long completions, document generation, agent loops). Grok 3 mini Reasoning (high) makes more sense when output volume is low and absolute reasoning quality justifies the premium.
Strengths. Grok 3 mini Reasoning (high) is strongest on Intelligence Index (14.6). gpt-oss-120b (low) leads on Coding Index (21.2), Intelligence Index (10.2).
Speed. On throughput, gpt-oss-120b (low) generates tokens at 240 tok/s versus 64 tok/s — about 73% faster. On time-to-first-token, Grok 3 mini Reasoning (high) responds in 730ms vs 810ms, which matters most for chat-style UIs.
Provider. SpaceXAI and OpenAI sell to overlapping but distinct developer audiences: SpaceXAI tends to ship frontier reasoning models with premium positioning, while OpenAI 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): Grok 3 mini Reasoning (high) costs $16.50 ($198/year); gpt-oss-120b (low) costs $12.60 ($151/year). At a smaller 5M-input/2M-output scale (single-developer tool or prototype): Grok 3 mini Reasoning (high) ≈ $2.50/run, gpt-oss-120b (low) ≈ $1.83/run. At agent/realtime scale (200M input / 100M output per million requests): Grok 3 mini Reasoning (high) ≈ $110/run, gpt-oss-120b (low) ≈ $84/run. gpt-oss-120b (low) becomes more attractive at higher volume — the absolute per-token pricing difference compounds when you ship at scale.
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
gpt-oss-120b (low) is cheaper overall. Its blended price (3:1 input/output ratio) is $0.25/M tokens vs $0.35/M for Grok 3 mini Reasoning (high).
It's a tie — both models win 1 benchmarks each across 12 evaluated categories. See the detailed benchmark chart above for per-category results.
gpt-oss-120b (low) generates tokens faster at 240 tok/s vs 64 tok/s. Grok 3 mini Reasoning (high) also has lower time-to-first-token (0.73s vs 0.81s).
Choose based on your priorities: gpt-oss-120b (low) for lower cost, both perform similarly on benchmarks, and gpt-oss-120b (low) for faster generation. For latency-sensitive apps, check the TTFT comparison above.