GPT-5.6 Sol vs GPT OSS 20B High: Specs & Benchmark Comparison
GPT-5.6 Sol and GPT OSS 20B High both come from OpenAI, GPT OSS 20B High was released in October 2025, and GPT-5.6 Sol followed 9 months later in July 2026. GPT OSS 20B High has a published size of about 20 billion parameters; OpenAI has not disclosed the parameter count of GPT-5.6 Sol.
We have 45 benchmark results for GPT-5.6 Sol and 2 benchmark results for GPT OSS 20B High, but they overlap on a single test: GPQA, where GPT-5.6 Sol scores 94.6% 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 50 times cheaper than GPT-5.6 Sol at $5 and $30. GPT-5.6 Sol takes the larger context window at 1M tokens, compared with 131K for GPT OSS 20B High. GPT-5.6 Sol accepts text and images as input, while GPT OSS 20B High accepts text.
| Characteristic | GPT-5.6 Sol | GPT OSS 20B High |
|---|---|---|
| Company | OpenAI | OpenAI |
| Release Date | July 9, 2026 | October 1, 2025 |
| Parameters | — | 20B |
| Multimodal | Yes | No |
| Context (input) | 1.1M | 131K |
| Context (output) | 128K | 131K |
| Input Price / 1M | $5.00 | $0.10 |
| Output Price / 1M | $30.00 | $0.50 |
| Average Score | 63.9% | 86.5% |
| Benchmarks | ||
| GPQA | 94.6% | 74.2% |
Visual Benchmark Comparison
Verdict
GPT-5.6 Sol leads in 2 out of 4 comparison categories.
Both models show comparable average scores: GPT-5.6 Sol — 0.6, GPT OSS 20B High — 0.9.
GPT OSS 20B High is 58.3x cheaper: input $0.10/1M vs $5.00/1M tokens.
GPT-5.6 Sol supports a larger context: 1M vs 131K tokens.
GPT-5.6 Sol is newer: released 7/9/2026 vs 10/1/2025.
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Frequently Asked Questions
Which is better for coding — GPT-5.6 Sol or GPT OSS 20B High?
Which model is cheaper — GPT-5.6 Sol or GPT OSS 20B High?
Which has a larger context window — GPT-5.6 Sol or GPT OSS 20B High?
The GPT-5.6 Sol 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-5.6 Sol or GPT OSS 20B High page. See also the complete list of AI model comparisons.