Model Comparison

Grok-1.5 vs Phi-3.5-mini-instructWhich is better in 2026?

Grok-1.5 significantly outperforms across most benchmarks.

Verdict: Grok-1.5 vs Phi-3.5-mini-instruct — which is better?

Grok-1.5 (by xAI) and Phi-3.5-mini-instruct (by Microsoft) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Grok-1.5 outperforms in 6 benchmarks (GPQA, GSM8k, HumanEval, MATH, MMLU, MMLU-Pro), while Phi-3.5-mini-instruct is better at 0 benchmarks. Grok-1.5 significantly outperforms across most benchmarks.

Choose Grok-1.5 if…

  • you want the strongest raw capability — it leads on 6 of 6 shared benchmarks

Choose Phi-3.5-mini-instruct if…

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

Performance Benchmarks

Comparative analysis across standard metrics

6 benchmarks

Grok-1.5 outperforms in 6 benchmarks (GPQA, GSM8k, HumanEval, MATH, MMLU, MMLU-Pro), while Phi-3.5-mini-instruct is better at 0 benchmarks.

Grok-1.5 significantly outperforms across most benchmarks.

Thu Jul 02 2026 • llm-stats.com

Arena Performance

Human preference votes

Context Window

Maximum input and output token capacity

Only Phi-3.5-mini-instruct specifies input context (128,000 tokens). Only Phi-3.5-mini-instruct specifies output context (128,000 tokens).

xAI
Grok-1.5
Input- tokens
Output- tokens
Microsoft
Phi-3.5-mini-instruct
Input128,000 tokens
Output128,000 tokens
Thu Jul 02 2026 • llm-stats.com

License

Usage and distribution terms

Grok-1.5 is licensed under a proprietary license, while Phi-3.5-mini-instruct uses MIT.

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

Grok-1.5

Proprietary

Closed source

Phi-3.5-mini-instruct

MIT

Open weights

Release Timeline

When each model was launched

Grok-1.5 was released on 2024-03-28, while Phi-3.5-mini-instruct was released on 2024-08-23.

Phi-3.5-mini-instruct is 5 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.3 years ago

Phi-3.5-mini-instruct

Aug 23, 2024

1.9 years ago

4mo 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

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

xAI
Higher GPQA score (35.9% vs 30.4%)
Higher GSM8k score (90.0% vs 86.2%)
Higher HumanEval score (74.1% vs 62.8%)
Higher MATH score (50.6% vs 48.5%)
Higher MMLU score (81.3% vs 69.0%)
Higher MMLU-Pro score (51.0% vs 47.4%)
Microsoft
Larger context window (128,000 tokens)
Has open weights

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Grok-1.5 and Phi-3.5-mini-instruct side-by-side, then vote on the output you prefer.

Grok-1.5
✓ Preferred
Phi-3.5-mini-instruct
Open in Playground
AI Model Comparison Table
Feature
xAI
Grok-1.5
Microsoft
Phi-3.5-mini-instruct

FAQ

Common questions about Grok-1.5 vs Phi-3.5-mini-instruct.

Which is better, Grok-1.5 or Phi-3.5-mini-instruct?

Grok-1.5 significantly outperforms across most benchmarks. Grok-1.5 is made by xAI and Phi-3.5-mini-instruct is made by Microsoft. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Grok-1.5 compare to Phi-3.5-mini-instruct in benchmarks?

Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%. Phi-3.5-mini-instruct scores GSM8k: 86.2%, ARC-C: 84.6%, RULER: 84.1%, PIQA: 81.0%, OpenBookQA: 79.2%.

What are the context window sizes for Grok-1.5 and Phi-3.5-mini-instruct?

Grok-1.5 supports an unknown number of tokens and Phi-3.5-mini-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 Phi-3.5-mini-instruct?

Key differences include licensing (Proprietary vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok-1.5 and Phi-3.5-mini-instruct?

Grok-1.5 is developed by xAI and Phi-3.5-mini-instruct is developed by Microsoft.

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