A brief overview of IBM's new 7 nm Telum mainframe CPU | Ars Technica
History of IBM Z Mainframe Processors | Semantic Scholar
IBM Z Telum Mainframe Processor at Hot Chips 33
CPU-Z | Softwares | CPUID
CPU-Z Benchmarks on various Synology models - Hope this helps give a rough idea of the CPU power difference between models. Also included 2 other VMs running on Windows Hyper-V Server. :
IBM Z15 Mainframe Processor Design - ServeTheHome
IBM to use Samsung 7nm EUV for Next-Gen POWER and z CPUs