Llama 3.1 405B vs Mistral Small 3
Head-to-head specifications
| Metric | Llama 3.1 405B | Mistral Small 3 | Difference |
|---|---|---|---|
| MMLU (general capability) | 88.6% | 72.0% | +16.6% |
| Context window | 128K tokens | 32K tokens | — |
| Price (input / output per 1M) | Open weights | Open weights | — |
| Access | Open weights | Open weights | — |
- Llama 3.1 405B leads general capability (MMLU 88.6% vs 72.0%).
- Llama 3.1 405B offers the larger context window, useful for long documents and codebases.
Verdict: Llama 3.1 405B or Mistral Small 3?
Llama 3.1 405B advantages
- General capability (+19%)
- Context window (+75%)
Mistral Small 3 advantages
- No decisive advantage on the tracked metrics.
Which should you choose?
- Choose the Llama 3.1 405B if you need the strongest reasoning and accuracy.
- Choose the Llama 3.1 405B if you work with long documents or large codebases.
Value for money
Both are open-weight models you can self-host, so running cost depends on your own infrastructure rather than API pricing.
Llama 3.1 405B vs Mistral Small 3: which should you choose?
Llama 3.1 405B — Meta large language model (2024) with a 128K-token context window and an MMLU score of 88.6%, released with open weights.
Mistral Small 3 — Mistral AI large language model (2025) with a 32K-token context window and an MMLU score of 72.0%, released with open weights.
Llama 3.1 405B vs Mistral Small 3: Llama 3.1 405B scores higher on the MMLU benchmark. Llama 3.1 405B leads general capability (MMLU 88.6% vs 72.0%). Llama 3.1 405B offers the larger context window, useful for long documents and codebases.
Capability and reasoning
On MMLU — a 57-subject benchmark of general knowledge and reasoning — the Llama 3.1 405B scores 88.6% versus 72.0%. MMLU is a useful proxy for raw knowledge but does not capture instruction-following, coding, tool use, latency or safety, so treat it as one signal among several.
Context window
The Llama 3.1 405B handles up to 128K tokens per request, which sets how much documentation, transcript or code it can reason over at once — decisive for retrieval-augmented and long-document workflows.
Pricing and access
Llama 3.1 405B is open weights and Mistral Small 3 is open weights. Proprietary models bill per token via API; open-weight models can be self-hosted, trading per-call cost for infrastructure you manage. For production, weigh throughput, rate limits and data-residency needs alongside headline price.
The verdict
Both are credible choices in the ai model comparison space; the specification table above lays out every metric so you can weigh the trade-offs that matter to you. Pick the one whose strengths line up with how you will actually use it.
Frequently asked questions
Is the Llama 3.1 405B better than the Mistral Small 3?
Llama 3.1 405B is the clearly stronger overall choice, winning most of the dimensions that matter. Llama 3.1 405B leads general capability (MMLU 88.6% vs 72.0%).
What is the main difference between the Llama 3.1 405B and the Mistral Small 3?
Llama 3.1 405B leads general capability (MMLU 88.6% vs 72.0%). Llama 3.1 405B offers the larger context window, useful for long documents and codebases.
Which is better value?
Both are open-weight models you can self-host, so running cost depends on your own infrastructure rather than API pricing.
Which should I choose?
Choose the Llama 3.1 405B if you need the strongest reasoning and accuracy. Choose the Llama 3.1 405B if you work with long documents or large codebases.
Methodology
Large language models are compared on the MMLU benchmark (a widely-cited 57-subject test of general knowledge and reasoning, reported as a percentage), maximum context window, and published API pricing per million input and output tokens. Open-weight models can also be self-hosted. Benchmarks capture only part of real-world quality, which also depends on tool use, latency, safety and task fit.