This is a newby question. I don't know much about displays. I have one of the original Apple Cinema Displays-20" ADC with the plastic housing. I bought it when the highest resolution for displays was 1024 x 768. It was a great screen and I hate to get rid of it so am thinking of using it with a new MBP as an external display. If I do, what sort of resolution will I get on it? Is the resolution determined by the display itself or by the software in the computer?