Model Comparison

Grok-1.5 vs Llama 3.1 405B Instruct

Llama 3.1 405B Instruct significantly outperforms across most benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

6 benchmarks

Grok-1.5 outperforms in 0 benchmarks, while Llama 3.1 405B Instruct is better at 6 benchmarks (GPQA, GSM8k, HumanEval, MATH, MMLU, MMLU-Pro).

Llama 3.1 405B Instruct significantly outperforms across most benchmarks.

Mon May 25 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Llama 3.1 405B Instruct specifies input context (128,000 tokens). Only Llama 3.1 405B Instruct specifies output context (128,000 tokens).

xAI
Grok-1.5
Input- tokens
Output- tokens
Meta
Llama 3.1 405B Instruct
Input128,000 tokens
Output128,000 tokens
Mon May 25 2026 • llm-stats.com

License

Usage and distribution terms

Grok-1.5 is licensed under a proprietary license, while Llama 3.1 405B Instruct uses Llama 3.1 Community License.

License differences may affect how you can use these models in commercial or open-source projects.

Grok-1.5

Proprietary

Closed source

Llama 3.1 405B Instruct

Llama 3.1 Community License

Open weights

Release Timeline

When each model was launched

Grok-1.5 was released on 2024-03-28, while Llama 3.1 405B Instruct was released on 2024-07-23.

Llama 3.1 405B Instruct is 4 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.2 years ago

Llama 3.1 405B Instruct

Jul 23, 2024

1.8 years ago

3mo newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

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Key Takeaways

xAI

No standout differentiators in the data we have for this pair.

Meta
Larger context window (128,000 tokens)
Has open weights
Higher GPQA score (50.7% vs 35.9%)
Higher GSM8k score (96.8% vs 90.0%)
Higher HumanEval score (89.0% vs 74.1%)
Higher MATH score (73.8% vs 50.6%)
Higher MMLU score (87.3% vs 81.3%)
Higher MMLU-Pro score (73.3% vs 51.0%)

Detailed Comparison

AI Model Comparison Table
Feature
xAI
Grok-1.5
Meta
Llama 3.1 405B Instruct

FAQ

Common questions about Grok-1.5 vs Llama 3.1 405B Instruct.

Which is better, Grok-1.5 or Llama 3.1 405B Instruct?

Llama 3.1 405B Instruct significantly outperforms across most benchmarks. Grok-1.5 is made by xAI and Llama 3.1 405B Instruct is made by Meta. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Grok-1.5 compare to Llama 3.1 405B Instruct in benchmarks?

Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%. Llama 3.1 405B Instruct scores ARC-C: 96.9%, GSM8k: 96.8%, API-Bank: 92.0%, Multilingual MGSM (CoT): 91.6%, HumanEval: 89.0%.

What are the context window sizes for Grok-1.5 and Llama 3.1 405B Instruct?

Grok-1.5 supports an unknown number of tokens and Llama 3.1 405B Instruct supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Grok-1.5 and Llama 3.1 405B Instruct?

Key differences include licensing (Proprietary vs Llama 3.1 Community License). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok-1.5 and Llama 3.1 405B Instruct?

Grok-1.5 is developed by xAI and Llama 3.1 405B Instruct is developed by Meta.