The first thing to take a look at is the balance between the physical resources on the machine (CPU, Memory, disk) and the load on the server (# of SAN/NAS disks being monitored, VM's, FC switches, physical servers). I'd highly recommend taking a look at Chapter 5 of the STM Admin Guide which is a full deployment guide to help you correctly size your server for the load. Based upon that insight, it might make sense to increase physical resources, deploy proxy agents, allocate memory to services through configuration changes, or other steps.
Second, what version of STM are you on? In STM 5.7, we added the "Storage Manager Health Status Overview" to help customers get quicker insight into these types of questions.