parent.parent.parent or FindObjectWithTag?

I'm wondering which one is faster, and possibly if anyone knows at what point which one would become slower.

The object my component is on that I want to get is tagged already so it is possible to get it through a tag, but in my head parent.parent.parent.getComponent would be faster, but I'm not sure. Even then the possibility of GetComponentInParent is still there.

Does anyone know definitively which one is faster?