Claude Opus 5 vs Qwen3.8
I ran an experiment. Have Qwen3.8 and Claude Opus 5 try to optimize a codebase for performance. I wanted to see which was better and how far the gap was between them.
These models are very different from one another. Opus 5 is one of the top frontier models. Qwen3.8 is a model I could run locally, in my case on a Framework Desktop. For the harnesses, I used the claude CLI and opencode (for Qwen3.8).
Going in I knew Opus was the better model. This wasn’t about finding the winner. It was about seeing how far local models have come and what I could squeeze out of Qwen3.8.

