I have a 2007 iMac 24inch and I was reading somewhere about there is the ability to boot from an external USB2.0 or FireWire drive. Is this true, and is it worth it? I would like to get a external drive and boot Vista from it, for gaming. Im not sure if Fiber or USB 2.0 is fast enough compared to the internal drive!? Has anyone done this and if so is it possible to make this work effectively?