Gemini 3.1 Flash TTS Preview vs Llama 3.1 405B Instruct
Gemini 3.1 Flash TTS Preview (2026) and Llama 3.1 405B Instruct (2024) are compact production models from Google DeepMind and AI at Meta. Gemini 3.1 Flash TTS Preview ships a 16k-token context window, while Llama 3.1 405B Instruct ships a 128k-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Gemini 3.1 Flash TTS Preview is ~140% cheaper at $1/1M; pay for Llama 3.1 405B Instruct only for long-context analysis.
Decision scorecard
Local evidence first| Signal | Gemini 3.1 Flash TTS Preview | Llama 3.1 405B Instruct |
|---|---|---|
| Best for | general production evaluation | provider-routed production |
| Decision fit | General | RAG, Long context, and Classification |
| Context window | 16k | 128k |
| Cheapest output | - | $2.40/1M tokens |
| Provider routes | 1 tracked | 11 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Use Gemini 3.1 Flash TTS Preview when your own prompt tests beat the comparison signals; the local data does not show a decisive standalone advantage yet.
- Llama 3.1 405B Instruct has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Llama 3.1 405B Instruct has broader tracked provider coverage for fallback and procurement flexibility.
- Llama 3.1 405B Instruct uniquely exposes Structured outputs in local model data.
- Local decision data tags Llama 3.1 405B Instruct for RAG, Long context, and Classification.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Gemini 3.1 Flash TTS Preview
Unavailable
Cheapest tracked route/tier: Google AI Studio
Llama 3.1 405B Instruct
$2,520
Cheapest tracked route/tier: AWS Bedrock
Cost delta unavailable until both models have sourced input and output token prices.
Switch friction
- No overlapping tracked provider route is sourced for Gemini 3.1 Flash TTS Preview and Llama 3.1 405B Instruct; plan for SDK, billing, or endpoint changes.
- Llama 3.1 405B Instruct adds Structured outputs in local capability data.
- No overlapping tracked provider route is sourced for Llama 3.1 405B Instruct and Gemini 3.1 Flash TTS Preview; plan for SDK, billing, or endpoint changes.
- Check replacement coverage for Structured outputs before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-04-15 | 2024-07-23 |
| Context window | 16k | 128k |
| Parameters | — | 405B |
| Architecture | Decoder Only | Decoder Only |
| License | Proprietary | Llama 3 Community |
| Openness | Proprietary | Open weights |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | - | 2023-12 |
Pricing and availability
| Pricing attribute | Gemini 3.1 Flash TTS Preview | Llama 3.1 405B Instruct |
|---|---|---|
| Input price | $1/1M tokens | $2.40/1M tokens |
| Output price | - | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 3.1 Flash TTS Preview | Llama 3.1 405B Instruct |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | No | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Deep dive
The capability footprint differs most on structured outputs: Llama 3.1 405B Instruct. 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: Gemini 3.1 Flash TTS Preview has $1/1M input tokens and Llama 3.1 405B Instruct has $2.40/1M input tokens. Provider availability is 1 tracked routes versus 11. Treat unknown pricing as an integration gap, then verify the route you will actually call before estimating production spend.
Choose Gemini 3.1 Flash TTS Preview when provider fit and lower input-token cost are central to the workload. Choose Llama 3.1 405B Instruct when long-context analysis, larger context windows, and broader provider choice 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 has a larger context window, Gemini 3.1 Flash TTS Preview or Llama 3.1 405B Instruct?
Llama 3.1 405B Instruct supports 128k tokens, while Gemini 3.1 Flash TTS Preview supports 16k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Is Gemini 3.1 Flash TTS Preview or Llama 3.1 405B Instruct open source?
Gemini 3.1 Flash TTS Preview is listed under Proprietary. Llama 3.1 405B Instruct is listed under Llama 3 Community. 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 structured outputs, Gemini 3.1 Flash TTS Preview or Llama 3.1 405B Instruct?
Llama 3.1 405B Instruct has the clearer documented structured outputs signal in this comparison. If structured outputs is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Gemini 3.1 Flash TTS Preview and Llama 3.1 405B Instruct?
Gemini 3.1 Flash TTS Preview is available on Google AI Studio. Llama 3.1 405B Instruct is available on OctoAI API (Deprecated), Together AI, Fireworks AI, IBM watsonx, and Scale AI GenAI Platform. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
When should I pick Gemini 3.1 Flash TTS Preview over Llama 3.1 405B Instruct?
Gemini 3.1 Flash TTS Preview is ~140% cheaper at $1/1M; pay for Llama 3.1 405B Instruct only for long-context analysis. If your workload also depends on provider fit, start with Gemini 3.1 Flash TTS Preview; if it depends on long-context analysis, run the same evaluation with Llama 3.1 405B Instruct.
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Last reviewed: 2026-06-15. Data sourced from public model cards and provider documentation.