ResWatcher is a lightweight and portable utility that displays the resource usage (CPU/Memory/Hard disk/Network) of your system.

ResWatcher Features:

• Free.
• Portable (No installation required).
• Allows you to monitor your total download and total upload (extremely useful feature when bandwidth is limited).
• Displays the top 5 processes in terms of CPU usage, making it easy to find the processes that slow your system down.
• Minimizes to the traybar in order to give your more taskbar space for your important applications.

http://www.fluxbytes.com/software-releases/reswatcher-is-now-available/