It's the last question before I buy the MBA. I have a program that can run under Win or MAC.That's a Picture convert and compile program work with my project . This program needs 100% CPU to and last 15 minutes to work under my old Pemtium M 1.6Ghz notebook. Usually I do my job use my notebook in home or my desktop PC in office.But occasionally I need to do some compile outside the office. So I really need to know whether the MBA will definitely shutdown one core when the CPU usage is 100% and last 15 minutes? Or maybe you can tell me if the MBA will shutdown when rendering a project in Mayar or 3D Max last 15 minutes. It's important to me before I buy the MBA. I just need a light notebook and I can do some hard job occassionally, but reliable. I like a Fujisu S6510 too,but it is too expensive and heaver than MBA. Thanks for your reply.