It's indeed Blender Guru's tutorial, I was following him to learn some of the more advanced techniques. It's a great way to learn but you still need to do your own thing.

As for the configuration, Blender is pretty well optimized, but you still need to pay attention to the number of objects that you put into a scene. This doesn't really affect you if you are using Eevee, but for Cycles you need a stronger work station if you don't want to wait too much rendering.