Grok 4 vs Llama 3.1 405B Instruct
Grok 4 (2025) and Llama 3.1 405B Instruct (2024) are frontier reasoning models from xAI and AI at Meta. Grok 4 ships a 256k-token context window, while Llama 3.1 405B Instruct ships a 128k-token context window. On pricing, Grok 4 costs $1.25/1M input tokens versus $2.40/1M for the alternative. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Grok 4 is ~92% cheaper at $1.25/1M; pay for Llama 3.1 405B Instruct only for provider fit.
Decision scorecard
Local evidence first| Signal | Grok 4 | Llama 3.1 405B Instruct |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | Coding, RAG, and Agents | RAG, Long context, and Classification |
| Context window | 256k | 128k |
| Cheapest output | $2.50/1M tokens | $2.40/1M tokens |
| Provider routes | 4 tracked | 11 tracked |
| Shared benchmarks | 0 rows | 0 rows |
Decision tradeoffs
- Grok 4 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Grok 4 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Grok 4 for Coding, RAG, and Agents.
- Llama 3.1 405B Instruct has the lower cheapest tracked output price at $2.40/1M tokens.
- 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 4
$1,625
Cheapest tracked route/tier: xAI Console
Llama 3.1 405B Instruct
$2,520
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $895. 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 $0.10/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Provider overlap exists on Microsoft Foundry; start route-level A/B tests there.
- Grok 4 is $0.10/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Grok 4 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-07-09 | 2024-07-23 |
| Context window | 256k | 128k |
| Parameters | — | 405B |
| Architecture | decoder only | 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 4 | Llama 3.1 405B Instruct |
|---|---|---|
| Input price | $1.25/1M tokens | $2.40/1M tokens |
| Output price | $2.50/1M tokens | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 | Llama 3.1 405B Instruct |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | 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 vision: Grok 4, multimodal input: Grok 4, reasoning mode: Grok 4, function calling: Grok 4, tool use: Grok 4, and code execution: Grok 4. 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 4 lists $1.25/1M input and $2.50/1M 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 4 lower by about $0.77 per million blended tokens. Availability is 4 providers versus 11, so concentration risk also matters.
Choose Grok 4 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 4 or Llama 3.1 405B Instruct?
Grok 4 supports 256k 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 4 or Llama 3.1 405B Instruct?
Grok 4 is cheaper on tracked token pricing. Grok 4 costs $1.25/1M input and $2.50/1M 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 4 or Llama 3.1 405B Instruct open source?
Grok 4 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 vision, Grok 4 or Llama 3.1 405B Instruct?
Grok 4 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Grok 4 or Llama 3.1 405B Instruct?
Grok 4 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Grok 4 and Llama 3.1 405B Instruct?
Grok 4 is available on Microsoft Foundry, OpenRouter, Replicate API, 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: 2026-06-01. Data sourced from public model cards and provider documentation.