Qwen 3.8 27B review: excellent model defaults to hilarious overthinking

marlene_zw · x · 2026-08-17

Simon Willison published an in-depth review of Alibaba's Qwen 3.8 27B model. Licensed under Apache 2.0, this vision-capable LLM shows impressive benchmark improvements over its predecessor and the closed-weight Qwen 3.7-Plus. Running a quantized version on both a MacBook Pro and an NVIDIA DGX Spark, Willison discovered that the model defaults to maximum reasoning depth. This causes it to engage in spectacular overthinking even for mundane tasks, rapidly consuming context windows and resources. While entertaining, this default configuration is inefficient for practical use.

Related event: Qwen 3.8 27B Review: Best Local Open Model with Near-Opus Performance(6 posts)→

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