he Reliability and Performance Monitor snap-in enables you to monitor server performance in real time. You can monitor hardware and application performance and create threshold alerts and performance reports. In terms of defining performance and reliability, performance describes how quickly the server completes the tasks it must accomplish. Reliability, on the other hand, is more a measure of how often the server performs exactly as you would expect in relation to its configuration.The Reliability and Performance Monitor snap-in also provides access to the Performance Monitor, which was available in Windows Server 2003, and the new Reliability Monitor. The Performance Monitor enables you to add counters to quickly view real-time hardware information such as the percent processor time and also view information related to system services such as HTTP (on a web server).