You use Performance Center's System Resource monitors to monitor a machine's system resource usage during a performance test run and isolate server performance bottlenecks.
A primary factor in a transaction's response time is its system resource usage. Using the Performance Center resource monitors, you can monitor the Windows, UNIX, SiteScope, and SNMP server on a machine during a test run, and determine why a bottleneck occurred on a particular machine.
The resource monitors are automatically enabled when you execute a test run. However, you must specify the machine you want to monitor and which resources to monitor for each machine. You can also add or remove machines and resources during the test run.