Side-by-side technical and economic comparison between OpenAI's GPT-5.6 Terra and Meta / Together's Llama 3.1 405B — Together AI.
• Llama 3.1 405B — Together AI: Classified as a Legacy Reference model (Deprecated on Together AI (Reference)).
| Metric | GPT-5.6 Terra | Llama 3.1 405B — Together AI | Advantage |
|---|---|---|---|
| Provider Organization | OpenAI | Meta / Together | — |
| Standard Input / 1M | $2.00 | $3.50 | GPT-5.6 Terra (43% lower) |
| Cached Input / 1M | $0.20 | None | GPT-5.6 Terra lower |
| Output / 1M | $12.00 | $3.50 | Llama 3.1 405B — Together AI lower |
| Context Window | 1.05M | 128k | GPT-5.6 Terra (1.05M) |
| Max Generation Tokens | 16.4k | 4.1k | GPT-5.6 Terra |
| Tokenizer Family | OpenAI o200k_base (200k vocabulary) | Meta Llama 3 Tiktoken BPE (~128k vocabulary) | — |
Opt for GPT-5.6 Terra when your engineering requirements prioritize OpenAI's ecosystem, specific tokenizer efficiencies (Exact BPE (o200k_base)), or when your expected prompt-to-completion ratios favor its $2/M input rate.
Opt for Llama 3.1 405B — Together AI when looking for Meta / Together's tooling integration, specific context window depth (128k tokens), or when output generation volume favors its $3.5/M rate.