MenuMeters is a set of CPU, memory disk and network monitoring tools for the Mac OS X from Raging Menace. It is under the GNU General Public License, making it free for all.

What sets it apart from other monitors that uses the menubar is that most of those monitors use the NSStatusItem API while MenuMeters uses SystemUIServer plugins (Menu Extras), meaning they can be re-ordered using command-drag and remember their positions in the menubar across log-ins and restarts.

Other notable features of the MenuMeter is that the CPU meter can display system load, either as a total percentage or broken out as user and system time. It is hotplug aware, and will show activity on FireWire and USB disks as they are mounted. The Memory Meter can display current memory usage as either a pie chart, thermometer, history graph, or as used/free totals. You can even optionally display a paging indicator light. While the Net Meter can display network throughput as arrows, bytes per second, and/or as a graph.

You will need MacOS X 10.2 (Jaguar), MacOS X 10.3 (Panther), or MacOS X 10.4 (Tiger) or PowerPC or Intel based Macintosh (Universal Binary) to install this monitor. And if you are installing over an older version of MenuMeters make sure to logout and login after installation in order to load the new version.

Download: [MenuMeters]