Are you sure that it is being converted properly? Also sometimes you may have 'Keep original' marked and your actual sub-div version in hiding beneath it...hello. i've found a little tutorial in web, which shows, how to model a human hand. first with rough poly model, which is then converted into subdiv. this convertion doesnt work by me. the converted model has the same amount of faces as poly model.
this is a poly smooth. not subdiv.Try this for subdiv.
Oops, my mistake. I see subdiv keeps the same amount of faces.this is a poly smooth. not subdiv.