To improve timing or optimize area in the Quartus® II software, you can change assignment settings by using the Assignment Editor or by changing timing requirements in the Timing Wizard.
The timing settings are saved in a project-specific file called a Quartus II Settings File (.qsf). For an explanation of the equations used to analyze the timing of the design, see the Quartus II Timing Analysis (PDF) chapter of the Quartus II Handbook. If the path is not meeting timing requirements, it will be displayed in red. (Note: In the Quartus II software user interface, most text in red is a warning sign that something is incorrect.) You can right-click on the red text, select List Paths from the menu, and then expand to see the exact path in the Messages window. You can also right-click on a path in the Timing Analysis window and in the Locate submenu, choose Locate in Timing Closure Floorplan to see where the nodes were placed in the device.