System Monitor (sysmon.exe) is a program in Windows 95, 98 and Me that is used to monitor various activities on a computer such as CPU usage or memory usage. The equivalent of System Monitor on Windows 2000 and XP is called Performance Monitor (perfmon.msc or perfmon.exe).
System Monitor can display information as a graph, a bar chart, or numeric values and can update information using a range of time intervals. The categories of information that you can monitor depend on which networking services are installed on your system, but they always include File System, Kernel, and Memory Manager. Other possible categories include Microsoft Network Client, Microsoft Network Server, and protocol categories.
This application is usually used to determine the cause of problems on a local or remote computer by measuring the performance of hardware, software services, and applications. System Monitor is not installed automatically during Windows setup, it must be installed manually using the Add/Remove Programs applet, located in the Control Panel.