FileInspect

Fileinspect Sidebar Gadget gives you detailed information about processes running on your computer. Not only does it show CPU load and RAM usage by each process, but also provides comprehensive description of the process in question.
Fileinspect Sidebar Gadget shows you a list of the most resource-heavy processes.

You can view a description of each process by clicking on the magnifying glass sign next to the process.
You can set the number of processes shown at the same time and customize the gadget to your liking from the sidebar gadget settings.