reduce FPS drops from Shuriken Particle System in 2D

The basic gist is i have a lot of thrown weapons which use the shuriken particle system, throwing one doesn't drop the fps bellow 60, however throwing multiple drops the FPS exponentially, can i get a list of things which can reduce the cost of the particle system, bearing in mind im working in 2d so i dont need to cast shadows or anything, basically anything which can reduce the fps drops