GPT-6 Astra vs GPT OSS 20B High: Specs & Benchmark Comparison

GPT-6 Astra and GPT OSS 20B High both come from OpenAI, GPT OSS 20B High was released in October 2025, and GPT-6 Astra followed 11 months later in September 2026. GPT OSS 20B High has a published size of about 20 billion parameters; OpenAI has not disclosed the parameter count of GPT-6 Astra.

We have 22 benchmark results for GPT-6 Astra and 2 benchmark results for GPT OSS 20B High, but they overlap on a single test: GPQA Diamond, where GPT-6 Astra scores 96.0% against 74.2%.

GPT OSS 20B High is the cheaper API at $0.10 per million input tokens and $0.50 per million output tokens, roughly 100 times cheaper than GPT-6 Astra at $10 and $50. GPT-6 Astra takes the larger context window at 1M tokens, compared with 131K for GPT OSS 20B High. GPT-6 Astra accepts text and images as input, while GPT OSS 20B High accepts text.

CharacteristicGPT-6 AstraGPT OSS 20B High
CompanyOpenAIOpenAI
Release DateSeptember 4, 2026October 1, 2025
Parameters20B
MultimodalYesNo
Context (input)1.1M131K
Context (output)128K131K
Input Price / 1M$10.00$0.10
Output Price / 1M$50.00$0.50
Average Score74.4%86.5%
Benchmarks
GPQA Diamond96.0%74.2%

Visual Benchmark Comparison

GPT-6 Astra
GPT OSS 20B High
GPQA Diamond1.0 vs 0.7
1.0
0.7

Verdict

GPT-6 Astra leads in 2 out of 4 comparison categories.

Overall Performance

Both models show comparable average scores: GPT-6 Astra — 0.7, GPT OSS 20B High — 0.9.

API Cost

GPT OSS 20B High is 100.0x cheaper: input $0.10/1M vs $10.00/1M tokens.

Context Window

GPT-6 Astra supports a larger context: 1M vs 131K tokens.

Recency

GPT-6 Astra is newer: released 9/4/2026 vs 10/1/2025.

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Frequently Asked Questions

Which is better for coding — GPT-6 Astra or GPT OSS 20B High?
Direct comparison on the SWE-Bench benchmark is not available. We recommend reviewing other metrics on the comparison page.
Which model is cheaper — GPT-6 Astra or GPT OSS 20B High?
GPT OSS 20B High is cheaper for input: $0.10 per 1M tokens vs $10.00.
Which has a larger context window — GPT-6 Astra or GPT OSS 20B High?
GPT-6 Astra supports a larger context: 1,050,000 tokens vs 131,072.

The GPT-6 Astra and GPT OSS 20B High comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-6 Astra or GPT OSS 20B High page. See also the complete list of AI model comparisons.