Base Processor Design
Data Intense work such as BI, Very Large Data Base, Classical OLTP or "cache killer" workloads (Object oriented code or context switching) will potentially run much better on S/390
CPU Intense work such as SPECint, Deep Computing, Graphic Rendering, will perform relatively poorly on S/390
* I/O scaling also varies: S/390 is better at 4k blocks (major ISVs tune to this) while the others are better at single byte movement (mostly RYO code).