My understanding is that Z mainframes have a number of unique features to support those use cases. Stuff like hot swapping CPUs, and hundreds of IO coprocessors

My understanding is that Z mainframes have a number of unique features to support those use cases. Stuff like hot swapping CPUs, and hundreds of IO coprocessors to avoid the main cores from getting blocked. Don't think they're just rebranded x86 machines, but not an expert.