80 points: A DIMM (double inline memory module) that contains the RAM for a modern computer typically contains 8 chips. So a 4GB DIMM would store one eighth of 4GB (namely, 512MB) on each chip. There are two ways to divide up the RAM among the chips: by column or by row. In the "by column" method, each of the 8 chips would to contain one eighth (that is, 1 bit) of each of the 4 billion bytes. In the "by row" method, each of the 8 chips would contain all 8 bits from one eighth of the bytes (that is, 512 million bytes).

• Which method is better? Why?
• What if 64 bits (8 bytes) are being read or written at a time? Hint: How many pins would each chip need?