Davinci Resolve

[zerram]

So, a friend recently pointed me to resolve.  I had been using 14 for a couple of weeks, and it has been butter smooth on my system from day 1.  Handles large files easily, and quickly.  Then, yesterday I tried to import an avi file, and it crashed on me.  Come to find out davinci does not like avi files.  Ok, that's fine I can make do with no problems there, but ever since that moment it has done nothing but stutter.  I have uninstalled, re-installed, uninstalled and removed program data files, installed davinci 15, back to 14 all with restarts in between.  Nothing has worked.  Tried looking at some playback setting in the program (that I never had to tweak before), and none of that has worked.  I'm assuming it's a driver/codec issue, but I'm not sure what to do about this at this point.  Any advise would be appreciated!