If you're not copying files or rendering videos, disk usage should be below 5 percent. Generally speaking, depending on your system configuration, your total memory usage should be below 60 percent. Memory usually won't be an issue unless you run out of it, in which case your computer will start using virtual memory, and that can cause your PC to slow down.
Applications that are running, even if you're not using them, and processes use part of your computer's memory, and that usage will increase as you use or launch more applications. Typically, when you're not actively using applications and your computer isn't working on anything specific, such as maintenance, your total CPU usage should be less than 30 percent. You'll notice that as a process starts to consume more resources, the color begins to change from a light- to a dark-shade of orange, making it easier to tell which one is causing the problem.
Task Manager also uses colors to highlight processes that use the most resources.
