Yup, the purpose of the rendering options is to allow you to optimize performance on a wide range of hardware by making compromises between what you need, what you want, and what your computer is capable of delivering. If you could just go to "max everything" on any computer there would be no purpose served in even having the sliders. Start with what you need, if performance is still good move on to stuff you think you might like. If you have performance issues no matter what you are faced with the unattractive options of buying an expensive new computer or doing without some things you feel you need.