Model Comparison

Grok-4 Heavy vs Jamba 1.5 Large

Grok-4 Heavy significantly outperforms across most benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

Grok-4 Heavy outperforms in 1 benchmarks (GPQA), while Jamba 1.5 Large is better at 0 benchmarks.

Grok-4 Heavy significantly outperforms across most benchmarks.

Tue Apr 14 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Cost data unavailable.

Lowest available price from all providers
Tue Apr 14 2026 • llm-stats.com
xAI
Grok-4 Heavy
Input tokens$0.00
Output tokens$0.00
Best providerUnknown Organization
AI21 Labs
Jamba 1.5 Large
Input tokens$2.00
Output tokens$8.00
Best providerAWS Bedrock
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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).

xAI
Grok-4 Heavy
Input- tokens
Output- tokens
AI21 Labs
Jamba 1.5 Large
Input256,000 tokens
Output256,000 tokens
Tue Apr 14 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Grok-4 Heavy supports multimodal inputs, whereas Jamba 1.5 Large does not.

Grok-4 Heavy can handle both text and other forms of data like images, making it suitable for multimodal applications.

Grok-4 Heavy

Text
Images
Audio
Video

Jamba 1.5 Large

Text
Images
Audio
Video

License

Usage and distribution terms

Grok-4 Heavy is licensed under a proprietary license, while Jamba 1.5 Large uses Jamba Open Model License.

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

Grok-4 Heavy

Proprietary

Closed source

Jamba 1.5 Large

Jamba Open Model License

Open weights

Release Timeline

When each model was launched

Jamba 1.5 Large was released on 2024-08-22, while Grok-4 Heavy's release date is not specified.

We can confirm Jamba 1.5 Large's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.

Grok-4 Heavy

—

Jamba 1.5 Large

Aug 22, 2024

1.6 years ago

Knowledge Cutoff

When training data ends

Grok-4 Heavy has a knowledge cutoff of 2024-12-31, while Jamba 1.5 Large has a cutoff of 2024-03-05.

Grok-4 Heavy has more recent training data (up to 2024-12-31), making it potentially better informed about events through that date compared to Jamba 1.5 Large (2024-03-05).

Grok-4 Heavy

Dec 2024

9 mo newer
Jamba 1.5 Large

Mar 2024

Outputs Comparison

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Key Takeaways

xAI
Supports multimodal inputs
Higher GPQA score (88.4% vs 36.9%)
AI21 Labs
Larger context window (256,000 tokens)
Has open weights

Detailed Comparison

AI Model Comparison Table
Feature
xAI
Grok-4 Heavy
AI21 Labs
Jamba 1.5 Large

FAQ

Common questions about Grok-4 Heavy vs Jamba 1.5 Large

Grok-4 Heavy significantly outperforms across most benchmarks. Grok-4 Heavy is made by xAI and Jamba 1.5 Large is made by AI21 Labs. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.
Grok-4 Heavy scores AIME 2025: 100.0%, HMMT25: 96.7%, GPQA: 88.4%, LiveCodeBench: 79.4%, USAMO25: 61.9%. Jamba 1.5 Large scores ARC-C: 93.0%, GSM8k: 87.0%, MMLU: 81.2%, Arena Hard: 65.4%, TruthfulQA: 58.3%.
Grok-4 Heavy supports an unknown number of tokens and Jamba 1.5 Large supports 256K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.
Key differences include multimodal support (yes vs no), licensing (Proprietary vs Jamba Open Model License). See the full comparison above for benchmark-by-benchmark results.
Grok-4 Heavy is developed by xAI and Jamba 1.5 Large is developed by AI21 Labs.