Just because you increased the buffer pools and installed all these
resources does not mean that OS/390 will let you use them.  You may need to
do some storage isolation or you may have some reverse storage isolation
going on.  My guess is you are paging your butt off or something crazy like
that.  Also, an additional CPU does not mean anything unless you were CPU
constrained.  You could have also had tasks in the system that were memory
constrainted and not able to absorb CPU that now can because of the extra
memory.  You need to get the MVS Performance and Tuning person to take a
look at what is going on.