What type of loop code on game engines? Recently I worked on a game on Spritekit Engine. My question is not about spritekit, but generaly about game engines. When I write a loop code and run it (eg while i lt 100000) my CPU usage goes to 100 , but when I run the test game there is no changes specially on CPU usage ,why is this so? (We know game engines runs in a loop that includes logic and graphic commands )