Can anyone help explain the strange way my deco system is behaving.? I am not that technically adept. I live in a three story house. A deco on each floor. At the top is ny study, the deco unit in ques

Hello I have a three story house with a M9 at each level. At the top floor i noticed slow wifi speeds. I found powering off the Deco at this level radicaly improved the wifi speeds! How can this be? I