The Windows 8 Task Manager has been significantly improved over previous versions of Windows. Some of the new changes include showing a total percent usage at the top of your Processes, which makes it easier to determine total memory and CPU usage, improved Performance graphs, a Startup tab to see startup processes and their impact to system performance, and the App history tab (as shown below) that gives you the total resources an app has used over a period of time. Press Ctrl + Shift + Esc to start exploring the new Task Manager.