Performance issue in APO Module

While running the Demand Planning Book in APO Module, (<b>Transaction Code :: /n sdp94)</b> with 150 users, we faced a huge performance issue in both (while doing screen navigation & saving data).

The planning book volume was for about 250 products and for large no of products across India. We are running it on HP Super Dom where the SEM Server had 8 CPUs and 32 GB RAM.

The life cache server was having 8 CPUs and 120 GB RAM.

Would like to know if somebody has faced similar problem and if yes, how the problem was then solved?