Llama 3.1 405B vs GPT-5.3 Codex
At a Glance
| Compare |  Llama 3.1 405BMeta |  GPT-5.3 CodexOpenAI |
|---|---|---|
| Pricing and Limits | ||
| Input priceFrom · USD / 1M tokens | Not reported | $1.75Openai ↗ · Sep 3, 2026 |
| Output priceFrom · USD / 1M tokens | Not reported | $14.00Openai ↗ · Sep 3, 2026 |
| Context windowMaximum documented tokens | 131K | 400K |
| Model facts checked | Aug 28, 2026View model evidence → | Sep 3, 2026View model evidence → |
Token prices are the lowest available sourced USD rates; input and output may use different providers. Cost ranking estimates output spend on LiveBench, not a full request bill. Ranking methodology →
Available Benchmarks
Side-by-Side Facts
| Field | Llama-3.1-405B | GPT-5.3-Codex |
|---|---|---|
| Developer | Meta | OpenAI |
| Family | Llama 3 1 405b | Gpt 5 3 |
| Model | Llama-3.1-405B | GPT-5.3-Codex |
| Version | Llama-3.1-405B | GPT-5.3-Codex |
| Lifecycle | active | active |
| Released | 2024-07-23 | Unknown |
| Knowledge cutoff | Unknown | 2025-08-31 |
| Input modalities | Text | Text, Image |
| Output modalities | Text | Text |
| Context window | 131K | 400K |
| Total parameters | 405.9B | Unknown |
| Active parameters | Unknown | Unknown |
| License | llama3.1 | Unknown |
| Open weights | Yes | No |
| API available | Yes | Yes |
| Self-hostable | Yes | No |
| Provider access | Together Ai (Standard) | Openai (Standard), Openrouter (Standard) |
| Capabilities | generation | chat, generation, reasoning, structured_outputs, tools |
Llama 3.1 405B Capabilities
GPT-5.3 Codex Capabilities
Related Comparisons
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Llama-3.1-405BMeta | vs | Grok 4.6xAI | cross-developer peerstext |
Llama-3.1-405BMeta | vs |  Qwen3.8-MaxQwen | cross-developer peerstext |
Llama-3.1-405BMeta | vs |  Kimi-K3Moonshot AI | cross-developer peerstext |
 MiniMax-M3MiniMax | vs | Llama-3.1-405BMeta | cross-developer peerstext |
Llama-3.1-405BMeta | vs |  GLM-5.3Z.ai | cross-developer peerstext |
Llama-3.1-405BMeta | vs |  Hy4 previewTencent | cross-developer peerstext |
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Llama-3.1-405BMeta | vs |  Mistral Large 3Mistral AI | cross-developer peerstext |
Primary Evidence
Sources and Freshness
Questions
Llama 3.1 405B vs GPT-5.3 Codex FAQs
Is Llama 3.1 405B or GPT-5.3 Codex better for coding?+
This comparison does not currently contain a protocol-matched coding benchmark for both Llama 3.1 405B and GPT-5.3 Codex, so Model Markets cannot name a coding leader from pricing, context size, or capability labels alone.
Which is cheaper, Llama 3.1 405B or GPT-5.3 Codex?+
Only GPT-5.3 Codex has a directly sourced input price: $1.75 per million tokens. Only GPT-5.3 Codex has a directly sourced output price: $14.00 per million tokens.
Which has a larger context window, Llama 3.1 405B or GPT-5.3 Codex?+
GPT-5.3 Codex has the larger sourced context window. Llama 3.1 405B supports 131K and GPT-5.3 Codex supports 400K.
Which performs better in benchmarks, Llama 3.1 405B or GPT-5.3 Codex?+
There is no overall benchmark winner: At least two independently verified, protocol-matched benchmarks are required for an overall winner.
Can Llama 3.1 405B or GPT-5.3 Codex be self-hosted?+
Llama 3.1 405B is the only model in this pair currently marked as self-hostable. Llama 3.1 405B is open weight; GPT-5.3 Codex is not marked open weight.
Can Llama 3.1 405B and GPT-5.3 Codex understand images?+
Llama 3.1 405B is not documented with image input; GPT-5.3 Codex is documented with image input. This reflects supported input modalities, not vision quality.
Which can generate longer answers, Llama 3.1 405B or GPT-5.3 Codex?+
Neither has a larger sourced maximum output. Llama 3.1 405B is — and GPT-5.3 Codex is 128K.
Do Llama 3.1 405B and GPT-5.3 Codex support reasoning and tool use?+
Llama 3.1 405B: none of these features are definitively sourced. GPT-5.3 Codex: reasoning, tool calling, and image input. Feature support does not establish relative quality.
Which is available from more inference providers, Llama 3.1 405B or GPT-5.3 Codex?+
Llama 3.1 405B has 1 sourced provider route; GPT-5.3 Codex has 2, so GPT-5.3 Codex has broader tracked availability.
Which offers better value, Llama 3.1 405B or GPT-5.3 Codex?+
There is no universal value winner. Compare the input and output prices above with the matched benchmark result for your workload: cheaper tokens can be offset by different quality, token usage, latency, or provider availability.