FreeMeter is designed to monitor your system performance without using too many resources.
In each bar graph meter, a red bar indicates 98% or higher utilization; yellow, 90% or greater; green less than 90%. Each graph can also have a blue horizontal line across it which represents the 30 second average for that meter. In FreeMeter Professional, you can change the percentage limits and the colors that are used.
You can quickly hide the FreeMeter window by double-clicking the title bar. To unhide it, double-click and FreeMeter system tray icon. While hidden, all the meters continue to gather data.