It sounds as if you have a component that is starting to fail. When it draws excessive current it gets warm and then on restart,because it is warm, it draws less current and works correctly. Can you substitute any of your plug in boards ie Graphics, just in case it is one of those? This type of fault can be a nighmare to find. In a workshop a can of freezer and a hair dryer would be used if substituting known good boards did not find the fault.
Alienware 17 R4 2017 review