DeepSeek V4 Pro vs Llama 3.1 405B
DeepSeek V4 Pro (2026) and Llama 3.1 405B (2024) are frontier reasoning models from DeepSeek and AI at Meta. DeepSeek V4 Pro ships a 1M-token context window, while Llama 3.1 405B ships a 128K-token context window. On Google-Proof Q&A, DeepSeek V4 Pro leads by 38.6 pts. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit. It focuses on practical selection signals rather than broad model-family marketing.
DeepSeek V4 Pro fits 8x more tokens; pick it for long-context work and Llama 3.1 405B for tighter calls.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-24 | 2024-07-23 |
| Context window | 1M | 128K |
| Parameters | 1.6T | 405B |
| Architecture | mixture of experts | decoder only |
| License | MIT | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | DeepSeek V4 Pro | Llama 3.1 405B |
|---|---|---|
| Input price | $0.43/1M tokens | - |
| Output price | $0.87/1M tokens | - |
| Providers | - |
Capabilities
| Capability | DeepSeek V4 Pro | Llama 3.1 405B |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
Benchmarks
| Benchmark | DeepSeek V4 Pro | Llama 3.1 405B |
|---|---|---|
| Google-Proof Q&A | 90.1 | 51.5 |
| HumanEval | 76.8 | 89.0 |
| Chatbot Arena | 1460.0 | 1228.0 |
| Massive Multitask Language Understanding | 90.1 | 88.6 |
Deep dive
On shared benchmark coverage, Google-Proof Q&A has DeepSeek V4 Pro at 90.1 and Llama 3.1 405B at 51.5, with DeepSeek V4 Pro ahead by 38.6 points; HumanEval has DeepSeek V4 Pro at 76.8 and Llama 3.1 405B at 89, with Llama 3.1 405B ahead by 12.2 points; Chatbot Arena has DeepSeek V4 Pro at 1460 and Llama 3.1 405B at 1228, with DeepSeek V4 Pro ahead by 232 points. The largest visible gap is 232 points on Chatbot Arena, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on reasoning mode: DeepSeek V4 Pro, function calling: DeepSeek V4 Pro, tool use: DeepSeek V4 Pro, and structured outputs: DeepSeek V4 Pro. Both models share the core language-model surface, 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.
Pricing coverage is uneven: DeepSeek V4 Pro has $0.43/1M input tokens and Llama 3.1 405B has no token price sourced yet. Provider availability is 3 tracked routes versus 0. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose DeepSeek V4 Pro when reasoning depth, larger context windows, and broader provider choice are central to the workload. Choose Llama 3.1 405B when provider fit are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, DeepSeek V4 Pro or Llama 3.1 405B?
DeepSeek V4 Pro supports 1M tokens, while Llama 3.1 405B supports 128K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is DeepSeek V4 Pro or Llama 3.1 405B open source?
DeepSeek V4 Pro is listed under MIT. Llama 3.1 405B is listed under Open Source. 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 reasoning mode, DeepSeek V4 Pro or Llama 3.1 405B?
DeepSeek V4 Pro 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.
Which is better for function calling, DeepSeek V4 Pro or Llama 3.1 405B?
DeepSeek V4 Pro has the clearer documented function calling signal in this comparison. If function calling is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for tool use, DeepSeek V4 Pro or Llama 3.1 405B?
DeepSeek V4 Pro has the clearer documented tool use signal in this comparison. If tool use is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run DeepSeek V4 Pro and Llama 3.1 405B?
DeepSeek V4 Pro is available on DeepSeek Platform, Fireworks AI, and OpenRouter. Llama 3.1 405B is available on the tracked providers still being sourced. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-05-14. Data sourced from public model cards and provider documentation.