Model Comparison

GPT OSS 120B vs Grok-1.5

GPT OSS 120B significantly outperforms across most benchmarks.

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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

GPT OSS 120B outperforms in 2 benchmarks (GPQA, MMLU), while Grok-1.5 is better at 0 benchmarks.

GPT OSS 120B significantly outperforms across most benchmarks.

Wed Apr 22 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
Wed Apr 22 2026 • llm-stats.com
OpenAI
GPT OSS 120B
Input tokens$0.09
Output tokens$0.45
Best providerDeepinfra
xAI
Grok-1.5
Input tokens$0.00
Output tokens$0.00
Best providerUnknown Organization
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Context Window

Maximum input and output token capacity

Only GPT OSS 120B specifies input context (131,072 tokens). Only GPT OSS 120B specifies output context (131,072 tokens).

OpenAI
GPT OSS 120B
Input131,072 tokens
Output131,072 tokens
xAI
Grok-1.5
Input- tokens
Output- tokens
Wed Apr 22 2026 • llm-stats.com

License

Usage and distribution terms

GPT OSS 120B is licensed under Apache 2.0, while Grok-1.5 uses a proprietary license.

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

GPT OSS 120B

Apache 2.0

Open weights

Grok-1.5

Proprietary

Closed source

Release Timeline

When each model was launched

GPT OSS 120B was released on 2025-08-05, while Grok-1.5 was released on 2024-03-28.

GPT OSS 120B is 17 months newer than Grok-1.5.

GPT OSS 120B

Aug 5, 2025

8 months ago

1.4yr newer
Grok-1.5

Mar 28, 2024

2.1 years ago

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

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Key Takeaways

OpenAI
Larger context window (131,072 tokens)
Has open weights
Higher GPQA score (80.1% vs 35.9%)
Higher MMLU score (90.0% vs 81.3%)
xAI

Detailed Comparison

AI Model Comparison Table
Feature
OpenAI
GPT OSS 120B
xAI
Grok-1.5

FAQ

Common questions about GPT OSS 120B vs Grok-1.5

GPT OSS 120B significantly outperforms across most benchmarks. GPT OSS 120B is made by OpenAI and Grok-1.5 is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.
GPT OSS 120B scores MMLU: 90.0%, CodeForces: 82.1%, GPQA: 80.1%, TAU-bench Retail: 67.8%, HealthBench: 57.6%. Grok-1.5 scores GSM8k: 90.0%, DocVQA: 85.6%, MMLU: 81.3%, HumanEval: 74.1%, MMMU: 53.6%.
GPT OSS 120B supports 131K tokens and Grok-1.5 supports an unknown number of tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.
Key differences include licensing (Apache 2.0 vs Proprietary). See the full comparison above for benchmark-by-benchmark results.
GPT OSS 120B is developed by OpenAI and Grok-1.5 is developed by xAI.