Greevar is dead-on. At this point you need to focus more on form and topology before worrying about Zbrush and rigging. These pages on the polycount wiki need to be in your bookmarks: http://wiki.polycount.com/BaseMesh?highlight=%28\bCategoryCharacterModeling\b%29…
More ram will not help you with that because subdividing a 7 million point tool would give you 28 million points which will put you well past the default poly limit. You should never need a 28 million point mesh, you need to work more efficiently.
Experimenting with substance designer procedurals with the painter. Mesh has 28 tris. baked using marmoset toolbag 3, thanks for all support to the people from polycount, really amazing place to learn. I have mentioned the Artstation link for more and high-resolution screenshots from different angles. On…