Grok Code Fast 1 vs Llama 3.1 405B Instruct
Grok Code Fast 1 (2025) and Llama 3.1 405B Instruct (2024) compare a coding-specialized model against a standalone API model. Grok Code Fast 1 ships a 262k-token context window, while Llama 3.1 405B Instruct ships a 128k-token context window. On pricing, Grok Code Fast 1 costs $0.20/1M input tokens versus $2.40/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Grok Code Fast 1 is coding-specialized model, while Llama 3.1 405B Instruct is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Grok Code Fast 1 | Llama 3.1 405B Instruct |
|---|---|---|
| Product type | Coding-specialized model | Standalone API model |
| Best for | custom coding agents, code generation, and tool loops | provider-routed production |
| Decision fit | Coding, RAG, and Agents | RAG, Long context, and Classification |
| Context window | 262k | 128k |
| Cheapest output | $1.50/1M tokens | $2.40/1M tokens |
| Provider routes | 3 tracked | 11 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok Code Fast 1 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok Code Fast 1 has the lower cheapest tracked output price at $1.50/1M tokens.
- Grok Code Fast 1 uniquely exposes Function calling and Tool use in local model data.
- Local decision data tags Grok Code Fast 1 for Coding, RAG, and Agents.
- 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 route or tier on this page.
Grok Code Fast 1
$535
Cheapest tracked route/tier: OpenRouter
Llama 3.1 405B Instruct
$2,520
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $1,985. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Llama 3.1 405B Instruct is $0.90/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Function calling and Tool use before moving production traffic.
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Grok Code Fast 1 is $0.90/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Grok Code Fast 1 adds Function calling and Tool use in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-08-27 | 2024-07-23 |
| Context window | 262k | 128k |
| Parameters | 314B | 405B |
| Architecture | mixture of experts | decoder only |
| License | Proprietary | Llama 3 Community |
| Openness | Proprietary | Open weights |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | 2023-12 |
Pricing and availability
| Pricing attribute | Grok Code Fast 1 | Llama 3.1 405B Instruct |
|---|---|---|
| Input price | $0.20/1M tokens | $2.40/1M tokens |
| Output price | $1.50/1M tokens | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | Grok Code Fast 1 | Llama 3.1 405B Instruct |
|---|---|---|
| Vision | No | No |
| Multimodal | No | No |
| Reasoning | No | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark rows are currently sourced for this pair.
Deep dive
The capability footprint differs most on function calling: Grok Code Fast 1 and tool use: Grok Code Fast 1. Both models share structured outputs, 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.
For cost, Grok Code Fast 1 lists $0.20/1M input and $1.50/1M output tokens on the cheapest tracked provider, while Llama 3.1 405B Instruct lists $2.40/1M input and $2.40/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Grok Code Fast 1 lower by about $1.81 per million blended tokens. Availability is 3 providers versus 11, so concentration risk also matters.
Choose Grok Code Fast 1 when coding workflow support, 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.
FAQ
Which has a larger context window, Grok Code Fast 1 or Llama 3.1 405B Instruct?
Grok Code Fast 1 supports 262k 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, Grok Code Fast 1 or Llama 3.1 405B Instruct?
Grok Code Fast 1 is cheaper on tracked token pricing. Grok Code Fast 1 costs $0.20/1M input and $1.50/1M output tokens. Llama 3.1 405B Instruct costs $2.40/1M input and $2.40/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok Code Fast 1 or Llama 3.1 405B Instruct open source?
Grok Code Fast 1 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 function calling, Grok Code Fast 1 or Llama 3.1 405B Instruct?
Grok Code Fast 1 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, Grok Code Fast 1 or Llama 3.1 405B Instruct?
Grok Code Fast 1 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 Grok Code Fast 1 and Llama 3.1 405B Instruct?
Grok Code Fast 1 is available on OpenRouter, Microsoft Foundry, and xAI Console. 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.
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Last reviewed: 2026-05-20. Data sourced from public model cards and provider documentation.