Performance Monitor is an MMC snap-in that is used to monitor system performance indicators and software reliability.

The Performance Monitor provides tools that measure the performance of a local or a remote computer on the network. Performance Monitor enables you to do the following:

• Collect data from local or remote computers. You can collect data from a single computer or multiple computers concurrently.
• View data as it is collected in real time, or historically from collected data.
• Have full control over the selection of what data will be collected by selecting which specific objects and counters will be collected.
• Choose the time interval that you want to use for collecting data points and the time period that will be used for data collection. Determine the format in which data will be viewed: NN inline, histogram bar, or report views.
• Create HTML pages for viewing data.
• Create specific configurations for monitoring data that can then be exported to other computers for performance monitoring.

The areas that can be controlled with the Reliability and Performance Monitor are:

• Resource Monitor
• Performance Monitor
• Data Collector Sets
• Reports

Read more about the Performance Monitor at:
http://technet.microsoft.com/en-us/library/cc749154.aspx.