Mac Application to defrag my Mac drive I work on media files as per my profession. I find my Mac (Mac Lion) going slower day by day. I think it will be beneficial to defrag the drive but didn't find any Apple tool for it. I want a an effective third party Mac defragmenter for my Mac drive.
Speed of access on HFS+ drives is not that affected by fragmentation unlike Windows file systems as OSX will do some defragmentation. A third party investigation is here.

You might be better off checking there is enough free space for new files.

There are some utilities to do defragmentation like iDefrag