I find that it slows down depending upon the time of day, sometimes even more depending which day of the week. Whether that is my internet connection being too slow or logged on user increase, it's hard to tell.
I also find, that it slows down when Ancestry is doing system changes. Last week, I had to switch browsers (IE to Edge), because IE wouldn't let me click on any buttons (they kept turning orange). This week, no problems. Me, IE or Ancestry? Maybe changes were being made that affected the browser. I don't know enough about these things and am happy to be corrected, but that's my 2 cents.