Qwen3.5-27B vs Qwen3.5 397B (Reasoning)

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

Agentic
Coding
Multimodal & Grounded
Reasoning
Knowledge
Instruction Following
Multilingual
Mathematics

Qwen3.5-27B· Qwen3.5 397B (Reasoning)

Quick Verdict

Pick Qwen3.5 397B (Reasoning) if you want the stronger benchmark profile. Qwen3.5-27B only becomes the better choice if coding is the priority or you need the larger 262K context window.

Qwen3.5 397B (Reasoning) is clearly ahead on the aggregate, 77 to 71. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Qwen3.5 397B (Reasoning)'s sharpest advantage is in agentic, where it averages 74.8 against 51.6. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 41.6% to 77%. Qwen3.5-27B does hit back in coding, so the answer changes if that is the part of the workload you care about most.

Qwen3.5-27B gives you the larger context window at 262K, compared with 128K for Qwen3.5 397B (Reasoning).

Operational tradeoffs

PriceFree*Free*
SpeedN/AN/A
TTFTN/AN/A
Context262K128K

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.

BenchmarkQwen3.5-27BQwen3.5 397B (Reasoning)
AgenticQwen3.5 397B (Reasoning) wins
Terminal-Bench 2.041.6%77%
BrowseComp61%78%
OSWorld-Verified56.2%70%
tau2-bench79%
CodingQwen3.5-27B wins
SWE-bench Verified72.4%60%
LiveCodeBench80.7%60%
HumanEval83%
SWE-bench Pro65%
SWE-Rebench59.9%
Multimodal & GroundedQwen3.5-27B wins
MMMU-Pro75%64%
OfficeQA Pro79%
ReasoningQwen3.5 397B (Reasoning) wins
LongBench v260.6%80%
MuSR85%
BBH91%
MRCRv282%
KnowledgeQwen3.5-27B wins
MMLU-Pro86.1%81%
SuperGPQA65.6%87%
GPQA85.5%89%
MMLU91%
HLE29%
FrontierScience81%
SimpleQA87%
Instruction FollowingQwen3.5-27B wins
IFEval95%89%
MultilingualQwen3.5 397B (Reasoning) wins
MMLU-ProX82.2%86%
MGSM91%
Mathematics
AIME 202393%
AIME 202495%
AIME 202594%
HMMT Feb 202389%
HMMT Feb 202491%
HMMT Feb 202590%
BRUMO 202592%
MATH-50093%
Frequently Asked Questions (8)

Which is better, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5 397B (Reasoning) is ahead overall, 77 to 71. The biggest single separator in this matchup is Terminal-Bench 2.0, where the scores are 41.6% and 77%.

Which is better for knowledge tasks, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5-27B has the edge for knowledge tasks in this comparison, averaging 80.6 versus 71.5. Inside this category, SuperGPQA is the benchmark that creates the most daylight between them.

Which is better for coding, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5-27B has the edge for coding in this comparison, averaging 77.6 versus 61.2. Inside this category, LiveCodeBench is the benchmark that creates the most daylight between them.

Which is better for reasoning, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5 397B (Reasoning) has the edge for reasoning in this comparison, averaging 82 versus 60.6. Inside this category, LongBench v2 is the benchmark that creates the most daylight between them.

Which is better for agentic tasks, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5 397B (Reasoning) has the edge for agentic tasks in this comparison, averaging 74.8 versus 51.6. Inside this category, Terminal-Bench 2.0 is the benchmark that creates the most daylight between them.

Which is better for multimodal and grounded tasks, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5-27B has the edge for multimodal and grounded tasks in this comparison, averaging 75 versus 70.8. Inside this category, MMMU-Pro is the benchmark that creates the most daylight between them.

Which is better for instruction following, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5-27B has the edge for instruction following in this comparison, averaging 95 versus 89. Inside this category, IFEval is the benchmark that creates the most daylight between them.

Which is better for multilingual tasks, Qwen3.5-27B or Qwen3.5 397B (Reasoning)?

Qwen3.5 397B (Reasoning) has the edge for multilingual tasks in this comparison, averaging 87.8 versus 82.2. Inside this category, MMLU-ProX is the benchmark that creates the most daylight between them.

Last updated: March 31, 2026

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