What is it for; to do object passive?
while working on assembly we can make objectives active or passive. is it useful for to speed up solidworks?
I'm not sure what you really ask, but passive and active functions are used in flow simulations. A good reading on this topic is available here: http://blog.alignex.com/mechanical-technical-blog-0/?Tag=SolidWorks%20Simulation
If you refer to supressed and unsupressed features, supressing some of the features may increase the speed and improve the response of SW, you can also simplify some of the elements (supress threads on bolts, for example) or use large assembly mode, default is 500 parts for LAM, you can reduce that to less, say, 100 or 200... That also may speed up the work.