Acrobat 8, 占了1.7G or 3.0G硬盤？

after installing acrobat 8

check control panel, add & remove software,found out:

typical installation: 1.7G
completely installation: more than 3.0G space

what happen? if talkes that much space , i d like to use 7.0 although 8.0 looks more attractive

any explaination? Thanks