Model Comparison

Jamba 1.5 Large vs Phi 4 ReasoningWhich is better in 2026?

Phi 4 Reasoning significantly outperforms across most benchmarks.

Verdict: Jamba 1.5 Large vs Phi 4 Reasoning — which is better?

Jamba 1.5 Large (by AI21 Labs) and Phi 4 Reasoning (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.

Jamba 1.5 Large outperforms in 0 benchmarks, while Phi 4 Reasoning is better at 3 benchmarks (Arena Hard, GPQA, MMLU-Pro). Phi 4 Reasoning significantly outperforms across most benchmarks.

Choose Jamba 1.5 Large if…

  • you want predictable pricing at $2.00/M input and $8.00/M output

Choose Phi 4 Reasoning if…

  • you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
  • you want the most recent training data — it shipped Apr 2025
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Performance Benchmarks

Comparative analysis across standard metrics

3 benchmarks

Jamba 1.5 Large outperforms in 0 benchmarks, while Phi 4 Reasoning is better at 3 benchmarks (Arena Hard, GPQA, MMLU-Pro).

Phi 4 Reasoning significantly outperforms across most benchmarks.

Tue Jun 09 2026 • llm-stats.com

Arena Performance

Human preference votes

Model Size

Parameter count comparison

384.0B diff

Jamba 1.5 Large has 384.0B more parameters than Phi 4 Reasoning, making it 2742.9% larger.

AI21 Labs
Jamba 1.5 Large
398.0Bparameters
Microsoft
Phi 4 Reasoning
14.0Bparameters
398.0B
Jamba 1.5 Large
14.0B
Phi 4 Reasoning

Context Window

Maximum input and output token capacity

Only Jamba 1.5 Large specifies input context (256,000 tokens). Only Jamba 1.5 Large specifies output context (256,000 tokens).

AI21 Labs
Jamba 1.5 Large
Input256,000 tokens
Output256,000 tokens
Microsoft
Phi 4 Reasoning
Input- tokens
Output- tokens
Tue Jun 09 2026 • llm-stats.com

License

Usage and distribution terms

Jamba 1.5 Large is licensed under Jamba Open Model License, while Phi 4 Reasoning uses MIT.

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

Jamba 1.5 Large

Jamba Open Model License

Open weights

Phi 4 Reasoning

MIT

Open weights

Release Timeline

When each model was launched

Jamba 1.5 Large was released on 2024-08-22, while Phi 4 Reasoning was released on 2025-04-30.

Phi 4 Reasoning is 8 months newer than Jamba 1.5 Large.

Jamba 1.5 Large

Aug 22, 2024

1.8 years ago

Phi 4 Reasoning

Apr 30, 2025

1.1 years ago

8mo newer

Knowledge Cutoff

When training data ends

Jamba 1.5 Large has a knowledge cutoff of 2024-03-05, while Phi 4 Reasoning has a cutoff of 2025-03-01.

Phi 4 Reasoning has more recent training data (up to 2025-03-01), making it potentially better informed about events through that date compared to Jamba 1.5 Large (2024-03-05).

Jamba 1.5 Large

Mar 2024

Phi 4 Reasoning

Mar 2025

1 yr newer

Outputs Comparison

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Key Takeaways

AI21 Labs
Larger context window (256,000 tokens)
Microsoft
Higher Arena Hard score (73.3% vs 65.4%)
Higher GPQA score (65.8% vs 36.9%)
Higher MMLU-Pro score (74.3% vs 53.5%)

Detailed Comparison

AI Model Comparison Table
Feature
AI21 Labs
Jamba 1.5 Large
Microsoft
Phi 4 Reasoning

FAQ

Common questions about Jamba 1.5 Large vs Phi 4 Reasoning.

Which is better, Jamba 1.5 Large or Phi 4 Reasoning?

Phi 4 Reasoning significantly outperforms across most benchmarks. Jamba 1.5 Large is made by AI21 Labs and Phi 4 Reasoning is made by Microsoft. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Jamba 1.5 Large compare to Phi 4 Reasoning in benchmarks?

Jamba 1.5 Large scores ARC-C: 93.0%, GSM8k: 87.0%, MMLU: 81.2%, Arena Hard: 65.4%, TruthfulQA: 58.3%. Phi 4 Reasoning scores FlenQA: 97.7%, HumanEval+: 92.9%, IFEval: 83.4%, OmniMath: 76.6%, AIME 2024: 75.3%.

What are the context window sizes for Jamba 1.5 Large and Phi 4 Reasoning?

Jamba 1.5 Large supports 256K tokens and Phi 4 Reasoning supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Jamba 1.5 Large and Phi 4 Reasoning?

Key differences include licensing (Jamba Open Model License vs MIT). See the full comparison above for benchmark-by-benchmark results.

Who makes Jamba 1.5 Large and Phi 4 Reasoning?

Jamba 1.5 Large is developed by AI21 Labs and Phi 4 Reasoning is developed by Microsoft.

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