Just right click the exe file you want to run, select "Properties" - "Compatibility"
Active "disable visual themes" and "disable desktop composition". Then "OK" and "Apply"
This can be used for computer games and big-resource-taking programs. After double clicked the exe file, Windows 8 will temporarily disable theme and desktop composition, saving these computer resources for you to run games or those programs.
This makes the speed of game and program faster. And once you quit the game or program, Windows 8 theme and desktop composition will come back.
What's more, if you feel that the resource is still not enough, then close all unnecessary processes in system tray at the right bottom of the screen.