Thanks for the report, Raymond, and for taking the time to check performance.

I am able to reliably reproduce the slowdowns in the benchmark between the 3.10.0a7 and 3.10.0b1 versions provided by the macOS installers on python.org. A similar slowdown is seen on both Intel and Apple Silicon Macs running macOS 11.3.1. Doing a quick build from source, I see no similar large differences between 3.10.0a7 and 3.10.0b1 on either macOS (with XC 12.5 Clang 12.0.5) or on a Debian Linux VM (with GCC 10.2.1). So it does seem to a difference in how the two macOS installers were built. There were some changes in the build env and process between a7 and b1. I will investigate further and report back here. But, the good news is that, AFAICT, there is no reason to suspect a general Python performance regression on this benchmark between a7 and b1.