Autocad2008 drawing size is big when paste something

Hi everybody,
i have a problem in autocad2008 that,some part of the drawings from earlier version autocad like 2006 & 2005 copied and pasted in autocad2008 and it took long time to pasted and the size of the file goes very larger. But the same part of the drawing i pasted in 2007 it quickly pasted and size also normal.Pl. help in this