Grok 4.1 Fast vs Llama 3.1 405B
Compare xAI and Meta (via Together AI) AI models
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
Grok 4.1 Fast
Llama 3.1 405B
Cost Differences
Llama 3.1 405B costs more than Grok 4.1 Fast
Feature Comparison
| Feature | Grok 4.1 Fast | Llama 3.1 405B |
|---|---|---|
| Provider | xAI | Meta (via Together AI) |
| Input Price | $0.20/1M tokens | $3.50/1M tokens |
| Output Price | $0.50/1M tokens | $3.50/1M tokens |
| Context Window | 2,000,000 tokens | 128,000 tokens |
| Max Output | 131,072 tokens | 32,768 tokens |
| Category | efficient | flagship |
| Capabilities | textreasoningcode | textcodereasoning |
| Release Date | 1/15/2026 | 7/23/2024 |
Grok 4.1 Fast vs Llama 3.1 405B: Which Should You Choose?
Choosing between Grok 4.1 Fast and Llama 3.1 405B depends on your priorities: cost efficiency, context length, or raw capability. Grok 4.1 Fast is the more affordable option at $0.20/1M input tokens — 94% cheaper than Llama 3.1 405B. Meanwhile, Grok 4.1 Fast offers a significantly larger context window at 2,000,000 tokens vs 128,000 for Llama 3.1 405B.
These models come from different providers — xAI and Meta (via Together AI) — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with xAI, switching to Meta (via Together AI)involves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
These models target different tiers: Grok 4.1 Fast is a efficient model while Llama 3.1 405B is flagship. This means they're optimized for different workloads. Llama 3.1 405B targets more demanding workloads, while Grok 4.1 Fast provides a cost-effective option for everyday tasks.
Output costs matter too. Grok 4.1 Fast charges $0.50/1M output tokens vs $3.50 for Llama 3.1 405B. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok 4.1 Fast has the edge here at $0.50/1M output tokens.
Best Use Cases
Choose Grok 4.1 Fast when:
- • Budget is a primary concern
- • You need a larger context window (2,000,000 tokens)
- • You need longer outputs (up to 131,072 tokens)
- • You're already using xAI's API ecosystem
- • You're running high-volume, latency-sensitive workloads
Choose Llama 3.1 405B when:
- • You're already using Meta (via Together AI)'s API ecosystem
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
Grok 4.1 Fast (xAI)
Llama 3.1 405B (Meta (via Together AI))
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