My 1T Time Machine that I purchased roughly 8 months ago is a royal pain in the butt. It backs up seemingly all of the time resulting in a very very very slow iMac. I can not figure out how to get into the Time Machine to back up once a day when I am asleep. instead it literally backs up probably 18-20 hours of the day. I can not even scroll without it effecting the scrolling ability or freezing my computer. What is the deal?