Im currently modelling this girl, and well im starting to have some problem with my Subdivision levels.
I might have pushed my computer too hard, almost every action in the highest subdivision levels takes a huge amount of time. So my question was is there some way i can generate a Displacment map in subdivision level 4 or 5 and then by starting from my low polymesh regain some of my details and subdivison levels with the displacment map? Another thing about my model that makes me whant too rebuild it is that ive used some Geometry HD sculpting on it and well i cant delete any subdivision anymore, Is there some kind of way to revers this?

If there is anyway you can do this i would be greatfull for some documentation on it, If there is any:p