Cheryl Watson’s Tuning Letter
Current CPU Chart: z Systems – May 2025
Presented in PDF and Excel format
Cheryl Watson’s z Systems CPU Chart provides a comprehensive list of 3,147 processor configurations from IBM that can run z/OS. This current version contains the most recent z17 series of models. For each processor the charts provide the number of physical CPUs, service units per second, software licensing group, MSUs (Millions of Service Units – both hardware and software) ratings, GA dates, MP (Multi-processor) degradation, and model codes. Especially important, is our estimated MIPS by workload (Average RNI, Low RNI, and High RNI).
Many installations use our CPU Chart in their RFPs (Request for Proposals) or performance guarantees, and most of our newsletter subscribers use it for their capacity planning estimates.
The CPU Chart is free to all Tuning Letter subscribers.
We now allow subscribers to distribute it throughout the company, even outside the sites counted in the subscription (but not to customers).
Download a PDF file with an extract from the z/OS 2.1 multi-image z Systems CPU Chart.