While Macs generally do not need to be "defragmented" on a routine basis the way PCs do, it can occasionally do some good to optimize the performance of the hard drive by consolidating contiguous blocks of data, particularly if the program or method used understands and respects OS X's adaptive hot-file clustering (aka the "hot zone" of most frequently-used programs). Prosoft's Drive Genius is one such program, and the company has updated its utility to include a new feature called Live Defrag that can optimize the boot drive without needing to be launched from a DVD
