RABN 3 vs RABN 4

A little bit about our environment. Adabas & Natural on Z/OS environment. We are in the process of migrating a major system off of our mainframe database and it may take two years. We also don’t expect the existing environment to grow. Are there any major CPU benefits to moving from RABN 3 to 4?

I have databases with RABN 3 and 4, i see no difference in performance