Following my post MySQL 8 is not always faster than MySQL 5.7, this time I decided to test very simple read-only CPU intensive workloads, when all data fits memory. In this workload there is NO IO operations, only memory and CPU operations. My Testing Setup Environment specification Release | Ubuntu 18.04 LTS (bionic) Kernel | [&]

https://www.percona.com/blog/2019/02/27/charset-and-collation-settings-impact-on-mysql-performance/