Claude Opus 5.5 designed a processor faster and smaller than the human-made one on the HWE benchmark

Claude Opus 5.5 designed a processor that outperformed a human-made VexRiscv processor on the HWE benchmark. The model started with a basic processor design and iteratively improved it. Performance was evaluated based on speed, measured by CoreMark scores (higher is better), and size (smaller is better). The Claude Opus 5.5 design achieved superior results in both speed and size compared to the VexRiscv, indicating a significant advancement in automated processor design.

This marks the first time an AI has designed a processor that is both faster and smaller than a human-engineered counterpart on a standard benchmark.