Shorter, used to be that you still had different CPU books (still might be so) but the leasing model where it often makes sense for IBM to ship more hw than les

Shorter, used to be that you still had different CPU books (still might be so) but the leasing model where it often makes sense for IBM to ship more hw than less is very popular with clients. Prime difference might be that from money point of view the way IBM handles it does end up in savings for the client (as it allows a pay-for-use/capacity rather than pay-for-hw model, and you can go 90% of the month in cheaper configuration and only pay for higher one for end of month/year ops). Another difference is that technically with IBM you're paying a license for microcode running on the CPUs, and you mix and match differently licensed versions to match your workload.