Use the utilities on your operating system to find out if your system is paging excessively.
Use the UNIX vmstat command, the UNIX sar command, or the Windows Task Manager, to get statistics on the number of running processes and the number of page-outs and swaps. Use this information to find out if the system is paging excessively, then make any necessary adjustments. You may want to put your swap files on special fast disks.