gpt-oss-20bvsQwen3.5
gpt-oss-20b | Qwen3.5 | |
|---|---|---|
| Specifications | ||
Parameters | 21B | 397B |
Context window | 128k | 1M |
| Benchmarks | ||
Coding SWE-Bench VerifiedReal coding tasks pulled from open-source projects — the AI has to find and fix actual bugs. A human-checked version of the original SWE-Bench. Higher is better. | 60.7% | 76.4%Best |
Multilingual coding SWE-Bench MultilingualLike SWE-Bench, but the coding problems span many programming languages, not just one. Tests how broadly the AI can code. Higher is better. | — | 69.3% |
Agentic terminal coding Terminal-Bench 2.0Can the AI work in a command-line terminal — running commands and finishing technical setup tasks the way a developer would? (Version 2.0 of the test.) Higher is better. | — | 52.5% |
Web browsing BrowseCompCan the AI browse the web and track down hard-to-find answers? Higher is better. | — | 69% |
Multidisciplinary reasoning Humanity's Last Exam · no toolsHumanity's Last Exam — extremely hard expert questions across many subjects, written so you can't just look up the answer. “No tools” means the AI answers on its own. Higher is better. | 10.9% | 28.7%Best |
Multidisciplinary reasoning Humanity's Last Exam · with toolsHumanity's Last Exam — extremely hard expert questions across many subjects. “With tools” means the AI is allowed to search the web or run code while answering. Higher is better. | 17.3% | — |
Science GPQA DiamondGraduate-level science questions in biology, physics, and chemistry — hard enough that subject-matter PhDs score around 65%. Higher is better. | 71.5% | 88.4%Best |
General knowledge MMLUA 57-subject multiple-choice exam — history, law, medicine, maths — that was the standard measure of how much a model knows from 2020 until roughly 2024, when frontier scores crowded into the high 80s and labs moved on to harder tests. The scores here were published years apart under different testing setups, so read them as a historical record rather than a like-for-like ranking. Higher is better. | 85.3% | — |
Agentic computer use OSWorld-VerifiedCan the AI actually operate a computer — clicking, typing, and using real apps — to finish tasks on its own? Higher is better. | — | 62.2% |
Chart reasoning CharXiv ReasoningCan the AI read and reason about complex charts and figures, not just text? Higher is better. | — | 80.8% |
Multimodal reasoning MMMU-ProA tougher version of MMMU — college-level questions that mix images, diagrams, and text together. Higher is better. | — | 79% |
Multimodal MMMUTests the AI on understanding images and text together across many college subjects. Higher is better. | — | 85% |
| Overview | ||
| Company | OpenAI | Qwen |
| Release date | Aug 5 2025 | Feb 16 2026 |
| Access | Open Weight | Open Weight |
Which is better: gpt-oss-20b or Qwen3.5?
Qwen3.5 leads gpt-oss-20b on 3 of the 3 benchmarks they both report (SWE-Bench Verified, Humanity's Last Exam, GPQA Diamond). gpt-oss-20b shipped 195 days before Qwen3.5, so benchmark comparisons should account for the intervening progress.
gpt-oss-20b has 21B parameters, while Qwen3.5 has 397B. Context windows are 128k (gpt-oss-20b) vs 1M (Qwen3.5).
On SWE-Bench Verified, Qwen3.5 leads at 76.4% vs gpt-oss-20b at 60.7%. On Humanity's Last Exam · no tools, Qwen3.5 leads at 28.7% vs gpt-oss-20b at 10.9%. On GPQA Diamond, Qwen3.5 leads at 88.4% vs gpt-oss-20b at 71.5%.
Frequently asked questions
gpt-oss-20b was released by OpenAI on Aug 5 2025.
Qwen3.5 was released by Qwen on Feb 16 2026.
Qwen3.5 leads on SWE-Bench Verified — gpt-oss-20b 60.7% vs Qwen3.5 76.4%.
Qwen3.5 leads on Humanity's Last Exam · no tools — gpt-oss-20b 10.9% vs Qwen3.5 28.7%.
gpt-oss-20b has a 128k context window; Qwen3.5 has 1M.