Consider whether the operating system has something to do with it, especially if it happens to have come from Bill's evil empire.
Task scheduling can be quirky to say the least- most of your CPU can go to something you don't care about that's in a looping or saving frenzy.
Also look at what's running on the new machine. If you can find something running that you don't need while you surf- kill it. If the hourglass problems goes away... you have found the troublemaker.