The size of the drive doesn't reduce. It's the free space. The OS is leaner now and when you upgrade, it will remove old files that it doesn't need. This frees up gigabytes of storage.
sorry for not searching but is there a way to get bootcamp to run after I've partitioned my HD using disc utility, formatting it for OSX? Bootcamp says that i have to use itself to partition the entire single HD in order to use for windows. Anyone can shed some light? thanx