Llama 3.1 405B Instruct vs o4-mini
Llama 3.1 405B Instruct (2024) and o4-mini (2025) are frontier reasoning models from AI at Meta and OpenAI. Llama 3.1 405B Instruct ships a 128K-token context window, while o4-mini ships a not-yet-sourced context window. On pricing, o4-mini costs $0.5/1M input tokens versus $2.4/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
o4-mini is ~380% cheaper at $0.5/1M; pay for Llama 3.1 405B Instruct only for provider fit.
Specs
| Released | 2024-07-23 | 2025-04-16 |
| Context window | 128K | — |
| Parameters | 405B | — |
| Architecture | decoder only | decoder only |
| License | Open Source | Proprietary |
| Knowledge cutoff | - | 2025-08 |
Pricing and availability
| Llama 3.1 405B Instruct | o4-mini | |
|---|---|---|
| Input price | $2.4/1M tokens | $0.5/1M tokens |
| Output price | $2.4/1M tokens | $2/1M tokens |
| Providers |
Capabilities
| Llama 3.1 405B Instruct | o4-mini | |
|---|---|---|
| Vision | ||
| Multimodal | ||
| Reasoning | ||
| Function calling | ||
| Tool use | ||
| Structured outputs | ||
| Code execution |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on vision: o4-mini, multimodal input: o4-mini, reasoning mode: o4-mini, function calling: o4-mini, tool use: o4-mini, and code execution: o4-mini. Both models share structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Llama 3.1 405B Instruct lists $2.4/1M input and $2.4/1M output tokens, while o4-mini lists $0.5/1M input and $2/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts o4-mini lower by about $1.45 per million blended tokens. Availability is 11 providers versus 4, so concentration risk also matters.
Choose Llama 3.1 405B Instruct when provider fit and broader provider choice are central to the workload. Choose o4-mini when coding workflow support and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship. This keeps the decision grounded in measurable tradeoffs instead of brand-level assumptions. It also helps separate model capability from provider packaging, which can change cost and latency.
FAQ
Which is cheaper, Llama 3.1 405B Instruct or o4-mini?
o4-mini is cheaper on tracked token pricing. Llama 3.1 405B Instruct costs $2.4/1M input and $2.4/1M output tokens. o4-mini costs $0.5/1M input and $2/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Llama 3.1 405B Instruct or o4-mini open source?
Llama 3.1 405B Instruct is listed under Open Source. o4-mini is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Llama 3.1 405B Instruct or o4-mini?
o4-mini has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Llama 3.1 405B Instruct or o4-mini?
o4-mini has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for reasoning mode, Llama 3.1 405B Instruct or o4-mini?
o4-mini has the clearer documented reasoning mode signal in this comparison. If reasoning mode is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Llama 3.1 405B Instruct and o4-mini?
Llama 3.1 405B Instruct is available on OctoAI API, Together AI, Fireworks AI, IBM watsonx, and Scale AI GenAI Platform. o4-mini is available on OpenAI API, OpenRouter, OpenAI Batch API, and Replicate API. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-04-24. Data sourced from public model cards and provider documentation.