Performance Drops Due To Windowed And Borderless Fullscreen

[Dominatiors]

So when jumping on Warframe today I noticed that my performance had dropped from my almost constant 60 fps (with VSync on) to 30-40 fps (still with VSync) went on to the forums and every forum entry i read said to turn off Local Reflections, and so I did and as far as I could tell it didn't do anything performance wise.  

 

Eventually I tried changing the game to fullscreen (since I play Warframe in Borderless Fullscreen) and my performance returned to normal, and upon changing it back to Borderless or Windowed I experienced said performance drops.

 

(Not sure if this is related but i installed some windows updates since yesterday when I last played)