Performance Monitor is a great tool for identifying performance bottlenecks! You can identify the source of performance problems that make your system performs slow or sometimes completely unusable. Performance Monitor is best suited when you are collecting performance statistics over a period of time such as, when users on regular basis report system degradation at specific times. You can set a number of performance counters (system components to monitor) related to your specific problem as to allow Performance Monitor to collect and save these data. To use Performance Monitor go to Server manager, expand Diagnostics\Performance\Monitoring Tools and click Performance Monitor. By default the graph is empty that is, no counters are selected to run. You can add counters to the real-time graph by clicking the green plus button on the toolbar. In addition, you can display data from other computers on the network. When monitoring a large number of resources, the real-time graph may become cluttered even though each counter appears in different color, however, selecting on counter from the list below the chart and pressing Ctrl+H would show the selected counter in bold and black. Other options are available from the top menu such as, change graph type and freeze display.
Although, I recommend that you play around with Performance Monitor to get acquainted with the tool, I would like to mention a couple of useful features. For instance, to save performance data you need to right click the node Performance Monitor on the left hand side and select New\Data Collector Set and follow the Create new data Collector Set wizard. Right clicking the graph and selecting Properties will load the properties page where you can set most of the appearance options. However, an important option is found in the Source tab. When you have set Performance Monitor to save data to a file then the Source tab is the place to go to open that file as your data source. One last note which I find very useful is the little option found at the bottom of the Add Counters window. Check the Show description feature to view a brief description of each counter you select. The short description is enough to help you decide if that particular counter is useful or not for the task at hand.