Data is capable of moving much faster than anyone else onboard, and he can do complicated math calculations in his head as easily as Picard or Riker can read a children's book. Why, then, doesn't Data oftentimes enter "super speed" mode (as shown in "Masks," "Hero Worship," "The Naked Now," off-screen in "The Offspring," etc.).
Out of universe, it was obviously not the Brent Spiner show, but what is the canon reason that Data many times didn't "take over?" For example, in "Night Terrors," Data and Troi are leisurely trying to find the correct element on the computer to produce an explosion. Of course, the process is slow, because Troi is just a humanoid, and she obviously cannot read as fast as Data could.
It is true that Troi helped Data in this investigation, but I have to believe that "super speed" Data would have eventually figured it out, too.