4.8 project opened in 4.11 frame rate dropped?

I opened a simple one room apartment scene that I created in 4.8 and it completely bogged down in 4.11 while previewing the matinee sequence. Can anyone tell me why?


You might have to rebuild lighting

Nope no go, the level is a disaster! Man, this software is by far the coolest and worst I have ever used all at the same time.
All the meshes look bad, no shadows, over exposed etc. etc.