differences between conservative ans non conservative forms in phase field or level set methods

hi friends,

what are the differences between conservative and non conservative forms of phase field and level set methods ??

do the conservative forms conserve the mass better ? are they more time and memory consuming?

I can simulate a droplet in air by non conservative form of phase field but when I change the settings to conservative form , it takes a lot of time to solve. there are big differences between the results obtained from conservative form in comparison with non conservative form.