Your settings can be accessed by pressing the ESC key once you log into the game. The settings related to your graphics can be found in the 'Display and Graphics'.
Optimize Settings:
You can use the 'Optimize Settings' button to choose a an option that contains a number of preselected settings. If you wish to reduce the strain on your graphics card or attempt to boost your fps, then you may wish to use the
'Optimize Settings for Performance' option.
Overheating
If you find that your graphic card is straining or overheating then optimizing the settings for performance is a good idea. You can also set the 'Present Interval' option to 'Interval One'. This will limit the FPS output of the client to what your monitor is capable of displaying, as opposed to attempting to get the maximum fps output possible. Note if you are using multiple monitors, it will divide your primary display's refresh rate by the number of monitors and limit the FPS to that number instead.