So, if you scale today's CPU/memory/mobo to something the size of a refrigerator, you're looking at maybe 1000x. So, following that, visualize the space take up by 1000 PC cases, then double it to account for the tape drives, thicker wires (for higher currents and voltages) and extra AC airflow. Then double it again because people had to have access to all these components all the time.