Unfortunately the subdivision surface modifier is very slow in the 2.8.
I did a test. Shape animation of an object with 10,000 quadrangular faces with a 2 subdivision (160,000 faces).
2.8 = 6 fps
2.79 = 60 fps
with 3 subdivisions
2.8 = 2 fps
2.79 = 60 fps
with 4 subdivisions
2.8 = 0.6 fps
2.79 = 60 fps
It seems to be back to the problems that had been solved a few years ago: