GPT-OSS 20B vs Qwen3.5-35B-A3B

Side-by-side benchmark comparison across agentic, coding, multimodal, knowledge, reasoning, and math workflows.

Agentic
Coding
Multimodal & Grounded
Reasoning
Knowledge
Instruction Following
Multilingual
Mathematics

GPT-OSS 20B· Qwen3.5-35B-A3B

Quick Verdict

Pick Qwen3.5-35B-A3B if you want the stronger benchmark profile. GPT-OSS 20B only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.

Qwen3.5-35B-A3B is clearly ahead on the aggregate, 67 to 35. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Qwen3.5-35B-A3B's sharpest advantage is in coding, where it averages 72.6 against 14.4. The single biggest benchmark swing on the page is LiveCodeBench, 11% to 74.6%.

Qwen3.5-35B-A3B is the reasoning model in the pair, while GPT-OSS 20B is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Qwen3.5-35B-A3B gives you the larger context window at 262K, compared with 128K for GPT-OSS 20B.

Operational tradeoffs

PriceFree*Free*
Speed313 t/sN/A
TTFT0.65sN/A
Context128K262K

Decision framing

BenchLM keeps the benchmark table and the operator tradeoffs on the same page so a better score does not hide a materially slower, pricier, or smaller-context model.

Runtime metrics show N/A when BenchLM does not have a sourced snapshot for that exact model. The scoring rules and freshness policy are documented on the methodology page.

BenchmarkGPT-OSS 20BQwen3.5-35B-A3B
AgenticQwen3.5-35B-A3B wins
Terminal-Bench 2.035%40.5%
OSWorld-Verified31%54.5%
BrowseComp61%
tau2-bench81.2%
CodingQwen3.5-35B-A3B wins
HumanEval23%
SWE-bench Verified14%69.2%
LiveCodeBench11%74.6%
SWE-bench Pro18%
React Native Evals64.3%
Multimodal & GroundedQwen3.5-35B-A3B wins
MMMU-Pro31%75.1%
OfficeQA Pro42%
ReasoningQwen3.5-35B-A3B wins
MuSR27%
LongBench v248%59%
MRCRv248%
KnowledgeQwen3.5-35B-A3B wins
MMLU85.3%
GPQA30%84.2%
SuperGPQA28%63.4%
MMLU-Pro53%85.3%
HLE1%
FrontierScience34%
SimpleQA29%
Instruction Following
IFEval91.9%
MultilingualQwen3.5-35B-A3B wins
MGSM61%
MMLU-ProX59%81%
Mathematics
AIME 202331%
AIME 202433%
AIME 202532%
HMMT Feb 202327%
HMMT Feb 202429%
HMMT Feb 202528%
BRUMO 202530%
MATH-50059%
Frequently Asked Questions (7)

Which is better, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B is ahead overall, 67 to 35. The biggest single separator in this matchup is LiveCodeBench, where the scores are 11% and 74.6%.

Which is better for knowledge tasks, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B has the edge for knowledge tasks in this comparison, averaging 79.3 versus 28.7. Inside this category, GPQA is the benchmark that creates the most daylight between them.

Which is better for coding, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B has the edge for coding in this comparison, averaging 72.6 versus 14.4. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.

Which is better for reasoning, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B has the edge for reasoning in this comparison, averaging 59 versus 42.4. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B has the edge for agentic tasks in this comparison, averaging 50.5 versus 33.1. Inside this category, OSWorld-Verified is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B has the edge for multimodal and grounded tasks in this comparison, averaging 75.1 versus 36. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, GPT-OSS 20B or Qwen3.5-35B-A3B?

Qwen3.5-35B-A3B has the edge for multilingual tasks in this comparison, averaging 81 versus 59.7. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 31, 2026

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