Gemini 1.5 Flash vs Llama 3.1 405B Instruct
Gemini 1.5 Flash (2024) and Llama 3.1 405B Instruct (2024) are compact production models from Google DeepMind and AI at Meta. Gemini 1.5 Flash ships a 1M-token context window, while Llama 3.1 405B Instruct ships a 128K-token context window. On pricing, Gemini 1.5 Flash costs $0.07/1M input tokens versus $2.4/1M for the alternative. This comparison covers specs, pricing, capabilities, benchmarks, provider availability, and production fit.
Gemini 1.5 Flash is ~3100% cheaper at $0.07/1M; pay for Llama 3.1 405B Instruct only for provider fit.
Decision scorecard
Local evidence first| Signal | Gemini 1.5 Flash | Llama 3.1 405B Instruct |
|---|---|---|
| Decision fit | RAG, Long context, and Classification | RAG, Long context, and Classification |
| Context window | 1M | 128K |
| Cheapest output | $0.3/1M tokens | $2.4/1M tokens |
| Provider routes | 2 tracked | 11 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Gemini 1.5 Flash has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Gemini 1.5 Flash has the lower cheapest tracked output price at $0.3/1M tokens.
- Local decision data tags Gemini 1.5 Flash for RAG, Long context, and Classification.
- Llama 3.1 405B Instruct has broader tracked provider coverage for fallback and procurement flexibility.
- 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 prices on this page.
Gemini 1.5 Flash
$135
Cheapest tracked route: GCP Vertex AI
Llama 3.1 405B Instruct
$2,520
Cheapest tracked route: AWS Bedrock
Estimated monthly gap: $2,385. Batch, cache, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on GCP Vertex AI; start route-level A/B tests there.
- Llama 3.1 405B Instruct is $2.1/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Provider overlap exists on GCP Vertex AI; start route-level A/B tests there.
- Gemini 1.5 Flash is $2.1/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
Specs
| Specification | ||
|---|---|---|
| Released | 2024-05-14 | 2024-07-23 |
| Context window | 1M | 128K |
| Parameters | — | 405B |
| Architecture | decoder only | decoder only |
| License | Unknown | Open Source |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Gemini 1.5 Flash | Llama 3.1 405B Instruct |
|---|---|---|
| Input price | $0.07/1M tokens | $2.4/1M tokens |
| Output price | $0.3/1M tokens | $2.4/1M tokens |
| Providers |
Capabilities
| Capability | Gemini 1.5 Flash | Llama 3.1 405B Instruct |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | No |
| Function calling | No | No |
| Tool use | No | No |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint is close: both models cover structured outputs. That makes context budget, benchmark fit, and provider maturity more important than a simple checklist. If your application depends on one integration detail, verify it against the provider route you plan to use, not just the base model listing.
For cost, Gemini 1.5 Flash lists $0.07/1M input and $0.3/1M output tokens, while Llama 3.1 405B Instruct lists $2.4/1M input and $2.4/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Gemini 1.5 Flash lower by about $2.26 per million blended tokens. Availability is 2 providers versus 11, so concentration risk also matters.
Choose Gemini 1.5 Flash when long-context analysis, larger context windows, and lower input-token cost are central to the workload. Choose Llama 3.1 405B Instruct when provider fit 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 1.5 Flash or Llama 3.1 405B Instruct?
Gemini 1.5 Flash supports 1M tokens, while Llama 3.1 405B Instruct supports 128K tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Gemini 1.5 Flash or Llama 3.1 405B Instruct?
Gemini 1.5 Flash is cheaper on tracked token pricing. Gemini 1.5 Flash costs $0.07/1M input and $0.3/1M output tokens. Llama 3.1 405B Instruct costs $2.4/1M input and $2.4/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Gemini 1.5 Flash or Llama 3.1 405B Instruct open source?
Gemini 1.5 Flash is listed under Unknown. Llama 3.1 405B Instruct 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 structured outputs, Gemini 1.5 Flash or Llama 3.1 405B Instruct?
Both Gemini 1.5 Flash and Llama 3.1 405B Instruct expose structured outputs. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Gemini 1.5 Flash and Llama 3.1 405B Instruct?
Gemini 1.5 Flash is available on GCP Vertex AI and 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 1.5 Flash over Llama 3.1 405B Instruct?
Gemini 1.5 Flash is ~3100% cheaper at $0.07/1M; pay for Llama 3.1 405B Instruct only for provider fit. If your workload also depends on long-context analysis, start with Gemini 1.5 Flash; if it depends on provider fit, run the same evaluation with Llama 3.1 405B Instruct.
Continue comparing
Last reviewed: 2026-05-16. Data sourced from public model cards and provider documentation.