Free system defrag software for mac

The Solar System has been invaded by an alien force!
As one of the few ships left in the remote Kuiper Belt, you have been thrown into the desperate battle raging around Neptune. Avoid the enemy sentry posts and take out their patrol ships, returning to the automated supply stations for repair and weapons. Get close to these and slow down to have your shields recharged.

System Manager came into being from a desire to roll the functionality of several of my favourite apps into one app, increase the functionality of a few of them, and free up some Dock space. Other functions were, and will be, added to increase its overall usefullness such as system log monitoring, file/folder permissions control, trash management, and possible improvements to Process Monitoring to name a few.
System Manager combines some of the best features from a variety of other monitoring apps all rolled into one application.
Main features:
- CPU Usage (Dual)
- System Load levels
- Memory Usage
- Network Activity
- Process listing with kill and renice a process
- System Preference Pane launching
- Uptime display
- IP Number display
- Classic status display in MenuBar, Dock, or any graph
- Launch and Shutdown Classic
Enhancements:
- you can disable CPU Monitor temp checking to improve performance
- you can show the CPU Monitor temperature in Celsius or Fahrenheit
- fixed a CPU Monitor ghosting remnant when drawing with Transparancy
- added pref to show/hide large CPU percentage readout seperately
- added pref to use non-transparent CPU border alarms
- dded transparent background option to the Load Monitor
- etwork monitor is now switchable amongst installed interfaces
- added Dock icon menuitem to select monitored network interface
- network data in and out values/plots/scale now reflect per sec values
- network refresh rate is adjustable instead of hard wired 2 seconds
- fixed a memory leak in the network monitor
- uptime monitor now remembers, displays and saves longest running uptime
- user definable large display font on the General preference tab
- moved the "Dock Icon Shows" radio buttons to the General pref tab
- fixed display of Classic status indicator when using graph transparency
- other minor performance improvements

System 47 is a nice screensaver that will display Star Trek LCARS interface on your screen with various interesting animations. More animations will be constantly added. So visit System47 web site often to download the latest version.
Enhancements:
- Recompiled. This version now works on either Intel-based or PowerPC-based Macs.

Requirements:
Mac OS X 10.0 or later.

Requirements:
Mac OS X 10.2 or later.

System Saver is an application-based screensaver. When sleeping, it displays icons from the System Suitcase (folder icons, the Finder icon, serial port icons, anything with type icl8) on a black field on your monitor.

The software has all the typical screensaver features (sleep now corner, user configurable delay before sleeping, etc), wake on mouse movement, etc. Supports multiple monitors.

Lego System is Seans first ever iconset is a major success! Generous with 60 icons, you can transform your whole system into a crazy legoland!

All icons are aquafied and look their best in 128x128 at 32bit mode.

Completly freeware.