Claude Opus 5.5 vs. Opus 5 on reasoning tasks: Cheaper, faster, but not better

The New Stack · 2 weeks ago · 31 ● 20 sources

An independent test compared Anthropic’s Claude Opus 5.5 with Opus 5 on reasoning prompts by running identical API calls and tracking time, token use, and cost. On the logic grid, Opus 5.5 cost $0.16 versus $0.27 for Opus 5 while finishing in 65 seconds versus 108 seconds. The cheaper and slightly faster model produced the same correct answers on two tests, but both models failed one constrained-ordering task and Opus 5.5 sometimes stopped early due to a refusal, so it was not consistently “better.”