I was experiencing some very choppy 3d performance myself , but after reading this thread I set Vsync on in Nvidia control panel, found the in-game FPS limit setting and dropped that down from 120 to 60 (srsly 120 is the default?!?) and I also
increased the crowd detail setting to maximum (I have a GTX970 card, so seriously doubt that I need to reduce detail settings!), and it's massively improved the chop situation.
It does still ocassionally get choppy though - I just saw it happen with bases loaded after each preceeding at bat was smooth, so maybe it's a CPU / calculation load exceeding a gfx load delay type thing or something?