With the release of OS 8.1 Apple changed the way hard drives are formatted to accept data. Apple greatly increased the number of potential allocation blocks changing from HFS to HFS+ under 8.1. This means that far less space on the hard drive is wasted on small files. Depending on the number and size of the files on your hard drive and the size of your hard drive you may recoup sizable amounts of space by formatting to the new standard. These tests were run on a PowerMac 9500 in a 1.4GB partition with 9,385 files using 829MB of space. It reflects a drive under heavy use with many small files. The data was obtained using MacSlack a freeware utility that lets you quickly asses how much space you would save given a smaller allocation block than you are currently using.