Why Xiaomi smartphone slow after OTA update

   The main reason is most of the user face lots of issue after OTA update in xiaomi devices because as we know before flashing any rom it is highly recommended that Wipe cache , dalvik cache etc.. so that rom can run efficeintly..  this is not happen when xiaomi send OTA update, 
  
   when Xiaomi send OT update  whole rom is flashed. and most people wont get chance or don' know of how to clearing and wiping cache and data.. and hence people face lots of bugs..& resulting slowing down the device
so you have to wipe cache afterevery OTA update to run your device smoothly