High CPU and memory usage in idle

Hi,

I have a lot of tabs opened in chrome, lets say, about 30. But when I don't do nothing, the CPU is being used between 25 and 40%, mostly by chrome.

But when I close Chrome and use only task manager I still get and average of 6% CPU usage and 33% of memory used. Coincidence or not when I started to move the mouse a lot I got CPU usages as high as 30%.

Some of process that are always working are: G-Buster Brownser Defense and IAstorDataSvc (32 bits). I'm using windows 8.

Can you help me ?

Cheers