Constant micro-freezes (PC)

Should be the  bug of the game itself and not the part of user hardware. For example when the wave of zombies start, the game micro freezes due to loading of a bunch models and etc. Same optimization problem is seen with the Zen Garden when switching the gardens, the game can just be stuck on loading screen or micro freeze the moment screen changes, basically game is not optimised for instant high load pressure, also as an example planting first plant at the start of the level also causes micro-freezes. Thanks!