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Grok-1.5 vs Llama 3.1 8B Instruct

Grok-1.5 and Llama 3.1 8B Instruct are closely matched at -2.7 and -2.6 on the LLM Stats Score.

xAI · Meta · Updated for 2026

Which is better?

Grok-1.5 and Llama 3.1 8B Instruct are closely matched on the overall LLM Stats Score at -2.7 and -2.6.

In the 4 individual benchmarks reported for both models, Grok-1.5 wins 4; this is a narrower head-to-head signal than the composite indexes.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose Grok-1.5

  • you value its reported benchmark strengths — it wins 4 of 4 exact shared results

Choose Llama 3.1 8B Instruct

  • you want the most recent training data — it shipped Jul 2024
  • you need open weights you can self-host or fine-tune

At a glance

The differences that matter most.

Grok-1.5
xAI
Llama 3.1 8B Instruct
Meta
Core performance indexes
LLM Stats Score
-2.7
#356
-2.6
#355
Reasoning
-2.2
#346
-3.6
#353
Coding
-0.9
#261
-2.3
#264
Cost, coverage & limits
Benchmark wins
4 of 4
0 of 4
Input price
— / M
$0.02 / M
Output price
— / M
$0.03 / M
Context window
—
131,072

Capability indexes

Additional strengths measured across groups of related public benchmarks

3 shared
Index
Grok-1.5
Llama 3.1 8B Instruct
Math
4.9#282
-2.5#317
Finance
4.7#177
-3.0#210
Legal
4.7#163
-3.0#195
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

9 reported for Grok-1.5 · 18 for Llama 3.1 8B Instruct

4 shared

Grok-1.5 outperforms in 4 benchmarks (GPQA, HumanEval, MMLU, MMLU-Pro), while Llama 3.1 8B Instruct is better at 0 benchmarks.

Grok-1.5 significantly outperforms across most benchmarks.

Mon Oct 19 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Llama 3.1 8B Instruct specifies input context (131,072 tokens). Only Llama 3.1 8B Instruct specifies output context (131,072 tokens).

xAI
Grok-1.5
Input- tokens
Output- tokens
Meta
Llama 3.1 8B Instruct
Input131,072 tokens
Output131,072 tokens
Mon Oct 19 2026 • llm-stats.com

License

Usage and distribution terms

Grok-1.5 is licensed under a proprietary license, while Llama 3.1 8B 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 8B 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 8B Instruct was released on 2024-07-23.

Llama 3.1 8B Instruct is 4 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.6 years ago

Llama 3.1 8B Instruct

Jul 23, 2024

2.2 years ago

3mo newer

Knowledge Cutoff

When training data ends

Llama 3.1 8B Instruct has a documented knowledge cutoff of 2023-12-31, while Grok-1.5's cutoff date is not specified.

We can confirm Llama 3.1 8B Instruct's training data extends to 2023-12-31, but cannot make a direct comparison without Grok-1.5's cutoff date.

Grok-1.5

—

Llama 3.1 8B Instruct

Dec 2023

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Grok-1.5 and Llama 3.1 8B Instruct side-by-side, then vote on the output you prefer.

Grok-1.5
✓ Preferred
Llama 3.1 8B Instruct
Open in Playground

FAQ

Common questions about Grok-1.5 vs Llama 3.1 8B Instruct.

Which is better, Grok-1.5 or Llama 3.1 8B Instruct?

Grok-1.5 and Llama 3.1 8B Instruct are closely matched on the LLM Stats Score at -2.7 and -2.6. Grok-1.5 is made by xAI and Llama 3.1 8B Instruct is made by Meta. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Grok-1.5 compare to Llama 3.1 8B 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 8B Instruct scores GSM-8K (CoT): 84.5%, ARC-C: 83.4%, API-Bank: 82.6%, IFEval: 80.4%, BFCL: 76.1%.

What are the context window sizes for Grok-1.5 and Llama 3.1 8B Instruct?

Grok-1.5 supports an unknown number of tokens and Llama 3.1 8B Instruct supports 131K 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 8B Instruct?

Key differences include LLM Stats Score (-2.7 vs -2.6), 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 8B Instruct?

Grok-1.5 is developed by xAI and Llama 3.1 8B Instruct is developed by Meta.

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