Resource Progress Bar can show you the current usage of your CPU, RAM, network, and Hard drive in real time.
Resource Progress Bar is portable and runs in the tray. If you click on it in the tray, it will bring up a small, resizable window with the letters C, M, N, and D and show you the current usage. Double-click that window, and it will close and return to the tray.
Right-click on the tray icon and you have numerous settings for this free app. Set it to the top, show or hide, max rate, opacity, choose which of the four choices to monitor, HDD and network LED, autostart, opacity, etc.
If you need to monitor your CPU, RAM, network, and Hard drive for any reason, Resource Progress Bar is small, free and useful with all the options available.