SQL Server未使用，但已分配表空间

I have ms sql databases that grow very large. Upon examination I find that there is a bunch of unused space in certain tables. I don't do many physical deletes, so I don't think that its just deleted records. DBCC SHRINK doesn't make the file smaller. But, if I dump the table to a new, empty database, the size goes down about 80%. Instead of the 7gb I have in this table in the current database, I end up with about 1.5gb in the fresh database. Its as if sql server is allocating too much memory. Anyone encountered this before? I'd like to be able to shrink the table by removing unused allocated space without having to create a whole new database.I have ms sql databases that grow very large. U