If I have in-canvas rendering turned on, my CPU will always be at 100%. Usually by the 50th iteration everything already looks fine and I don't need more iterations. Sometimes I accidentally forget to turn off in-canvas rendering or I forget to switch back to Model mode and it affects me using other programs or I go do something else while my CPU heats up and stays at 100% for hours. This seems like an easy option to hide in the settings somewhere and it will at least help me feel better about not melting my CPU.