at a glance

Qwen3.5-27BClaude Sonnet 4.6
providerAlibabaAnthropic
parameters27B~mid-size (est.)
context window256k tokens1m tokens

benchmarks

Cost (per 1M tokens) ?
Qwen3.5-27B
$0.11 in / $0.85 out
Claude Sonnet 4.6
$3.00 in / $15.00 out
SWE-bench Verified (software engineering) ?
Qwen3.5-27B
72.4%
Claude Sonnet 4.6
79.6%
Terminal Bench 2 (shell tasks) ?
Qwen3.5-27B
41.6%
Claude Sonnet 4.6
59.1%
GPQA Diamond (graduate science) ?
Qwen3.5-27B
85.5%
Claude Sonnet 4.6
89.9%
TAU-bench (agentic tool use) ?
Qwen3.5-27B
79.0%
Claude Sonnet 4.6
91.7%
MMMLU (multilingual knowledge) ?
Qwen3.5-27B
85.9%
Claude Sonnet 4.6
89.3%
MMMU (multimodal understanding) ?
Qwen3.5-27B
82.3%
Claude Sonnet 4.6
74.5%
Qwen3.5-27B Claude Sonnet 4.6 bold score = winner

what are these models?

Qwen3.5-27B is Alibaba’s 27-billion-parameter dense language model from the Qwen3.5 series. It is open-weight under Apache 2.0, runs on a single A100, and covers a wide range of tasks from coding to science to multimodal reasoning.

Claude Sonnet 4.6 is Anthropic’s mid-tier model, known for strong software engineering performance and a 1m token context window. It is closed-source and accessed via Anthropic’s API.

benchmark breakdown

Claude Sonnet 4.6 leads on five benchmarks. SWE-bench Verified (79.6% vs 72.4%), Terminal Bench 2 (59.1% vs 41.6%), GPQA Diamond (89.9% vs 85.5%), TAU-bench (91.7% vs 79.0%), and MMMLU (89.3% vs 85.9%) all favor Sonnet 4.6. The agentic tool use gap is the largest at 12.7 points.

Qwen3.5-27B wins only on multimodal. MMMU shows an 82.3% vs 74.5% advantage — a 7.8-point edge for Qwen. For visual and multimodal reasoning, Qwen3.5-27B is clearly stronger.

what people are saying

when to use Qwen3.5-27B

  • your task requires strong multimodal reasoning (images, diagrams, charts)
  • you need to self-host on a single A100 or equivalent
  • fine-tuning is part of your roadmap
  • data privacy or compliance prevents external API usage

when to use Claude Sonnet 4.6

  • software engineering and code understanding are your primary tasks
  • you need a 1m token context window for very long documents or full codebases
  • agentic multi-step tool-calling is important for your workflow
  • you want strong science and multilingual performance out of the box
  • you prefer a hosted API with no infrastructure overhead

amplifying strengths with fine-tuning

Qwen3.5-27B’s 7.8-point lead on MMMU makes it an especially strong foundation for multimodal fine-tuning. With 27B parameters that fit on a single A100, it’s practical for most teams — and when tuned on your visual or scientific data, it can deliver superior performance on those exact tasks.

For agentic workflows and coding, where Sonnet 4.6 leads by 7–12 points, fine-tuning Qwen3.5-27B on your tool-use traces or codebase can quickly close that gap. In practice, this turns a strong general model into a domain-optimized system that matches or exceeds performance where it matters most.

frequently asked questions

is qwen3.5-27b as good as claude sonnet 4.6?

on multimodal: better (7.8-point gap on mmmu). on science, software engineering, terminal tasks, agentic tool use, and multilingual: sonnet 4.6 has a clear edge. pick based on your task mix.

can i self-host qwen3.5-27b?

yes. at 27b parameters, it fits on a single a100-80gb at fp16, or with quantization on smaller gpus. together.ai and fireworks.ai also offer hosted access.

does sonnet 4.6 have a longer context window?

yes — 1m tokens vs 256k for qwen3.5-27b. for tasks that require processing very long contexts (full codebases, long documents), this is a meaningful structural advantage for sonnet 4.6.

which should i choose for a coding assistant?

claude sonnet 4.6 — it leads 79.6% vs 72.4% on swe-bench verified, a 7.2-point gap. if you need fine-tuning or self-hosting, qwen3.5-27b is the better foundation for customization.