300% of my CPU is being used? I ran a Java applet, and it used over 200% of my CPU....



It actually rose to over 400% after I took the screenshot.

How is this possible? Can someone explain why Activity Monitor shows a task as using more than 100% of my CPU?
The CPU percentages shown in Activity Monitor are 100% for each virtual core. If you have a quad core processor with hyperthreading, 'real' 100% is 800% in Activity Monitor.