Qwen 3.8 27B is excellent, but it defaults to overthinking things(simonwillison.net)
784 points by bilsbie 5 days ago | 376 comments
tl;dr: Qwen 3.8 27B is an Apache 2 licensed vision-capable model that runs impressively well from a 17GB file on consumer hardware, handling coding agents, bounding boxes, and tool calls competently. However, its default "xhigh" reasoning setting causes absurd overthinking—spending 21 minutes and 22K reasoning tokens on a simple SVG prompt—so users should dial reasoning down to low. The main drawback is speed (15-30 tokens/sec), though Multi-Token Prediction support via llama.cpp offers a ~72% boost.
HN Discussion:
  • Amazement that capable models now run on consumer/local hardware
  • Overthinking is a systemic issue from RL incentives across all current models
  • Users are building tools/forks to manually control and limit reasoning behavior
  • Current chain-of-thought reasoning approach is fundamentally a dead-end
  • Overthinking especially hurts dense models due to compounding speed penalties