The computer has two memory slots, DIMM A and DIMM B. DIMM A is located on top of the computer under the keyboard, and DIMM B is located on the bottom of the computer under the memory module cover.

DIMM A holds the basic memory module as configured from the factory. If you did not order additional memory, DIMM B is empty. Generally, if you add memory, you use DIMM B. If you are upgrading memory, you may need to install memory in DIMM A and DIMM B, depending on the extent of the upgrade.