NS Server Perfomance Issue

Hi,

I have NS Server created and about 4000 agents are installed they are communicating proper, but after increasing number of agents i.e 5000 my NS Server creates a perfomance issue, even i have created package server for each site.but altiris console is opening very slow, i am not able to push agents through altiris as well i have observed that the NS Events are processing very slow and increases.

please suggest.