I have a macbook 2.16ghz bought in June 07. Im wanting to buy a western digital 320gb external drive, which is supposed to be powered by the usb port. I read somewhere it takes 600 MA to power it, and someone said it took 1000MA to power it. In system profiler it says my macbook's usb supports 500MA, which really surprised me since its a pretty new computer. My question is if anyone has a 320gb passport drive on the same generation macbook i have that works. Or if you need a y cable to do it.