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Grok-1.5 vs Jamba 1.5 Large

Grok-1.5 and Jamba 1.5 Large are closely matched at -2.5 and 1.1 on the LLM Stats Score.

xAI · AI21 Labs · Updated for 2026

Which is better?

Grok-1.5 and Jamba 1.5 Large are closely matched on the overall LLM Stats Score at -2.5 and 1.1.

The models split the 4 individual benchmarks reported for both models evenly.

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

Choose Grok-1.5

  • you are already invested in the xAI ecosystem

Choose Jamba 1.5 Large

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

At a glance

The differences that matter most.

Grok-1.5
xAI
Jamba 1.5 Large
AI21 Labs
Core performance indexes
LLM Stats Score
-2.5
#328
1.1
#310
Reasoning
-2.0
#318
1.1
#300
Cost, coverage & limits
Benchmark wins
2 of 4
2 of 4
Input price
— / M
$2.00 / M
Output price
— / M
$8.00 / M
Context window
—
256,000

Capability indexes

Additional strengths measured across groups of related public benchmarks

3 shared
Index
Grok-1.5
Jamba 1.5 Large
Math
5.4#266
4.9#272
Finance
5.2#166
5.8#159
Legal
5.2#151
5.8#147
Conservative TrueSkill rating · higher is betterHow scores work

Individual benchmarks

9 reported for Grok-1.5 · 8 for Jamba 1.5 Large

4 shared

Grok-1.5 outperforms in 2 benchmarks (GSM8k, MMLU), while Jamba 1.5 Large is better at 2 benchmarks (GPQA, MMLU-Pro).

Both models are evenly matched across the benchmarks.

Mon Sep 07 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

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-1.5
Input- tokens
Output- tokens
AI21 Labs
Jamba 1.5 Large
Input256,000 tokens
Output256,000 tokens
Mon Sep 07 2026 • llm-stats.com

License

Usage and distribution terms

Grok-1.5 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-1.5

Proprietary

Closed source

Jamba 1.5 Large

Jamba Open Model License

Open weights

Release Timeline

When each model was launched

Grok-1.5 was released on 2024-03-28, while Jamba 1.5 Large was released on 2024-08-22.

Jamba 1.5 Large is 5 months newer than Grok-1.5.

Grok-1.5

Mar 28, 2024

2.4 years ago

Jamba 1.5 Large

Aug 22, 2024

2.0 years ago

4mo newer

Knowledge Cutoff

When training data ends

Jamba 1.5 Large has a documented knowledge cutoff of 2024-03-05, while Grok-1.5's cutoff date is not specified.

We can confirm Jamba 1.5 Large's training data extends to 2024-03-05, but cannot make a direct comparison without Grok-1.5's cutoff date.

Grok-1.5

—

Jamba 1.5 Large

Mar 2024

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Judge for yourself.

Run your own prompts against Grok-1.5 and Jamba 1.5 Large side-by-side, then vote on the output you prefer.

Grok-1.5
✓ Preferred
Jamba 1.5 Large
Open in Playground

FAQ

Common questions about Grok-1.5 vs Jamba 1.5 Large.

Which is better, Grok-1.5 or Jamba 1.5 Large?

Grok-1.5 and Jamba 1.5 Large are closely matched on the LLM Stats Score at -2.5 and 1.1. Grok-1.5 is made by xAI and Jamba 1.5 Large is made by AI21 Labs. 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 Jamba 1.5 Large in benchmarks?

Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%. Jamba 1.5 Large scores ARC-C: 93.0%, GSM8k: 87.0%, MMLU: 81.2%, Arena Hard: 65.4%, TruthfulQA: 58.3%.

What are the context window sizes for Grok-1.5 and Jamba 1.5 Large?

Grok-1.5 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.

What are the main differences between Grok-1.5 and Jamba 1.5 Large?

Key differences include LLM Stats Score (-2.5 vs 1.1), licensing (Proprietary vs Jamba Open Model License). See the full comparison above for benchmark-by-benchmark results.

Who makes Grok-1.5 and Jamba 1.5 Large?

Grok-1.5 is developed by xAI and Jamba 1.5 Large is developed by AI21 Labs.

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