HP DC7800 - Manual (Page 131)

4. Open both latches of the memory module socket (1), and insert the memory module into the socket
(2).
NOTE: A memory module can be installed in only one way. Match the notch on the module with
the tab on the memory socket.
A DIMM must occupy the black DIMM1 socket.
For maximum performance, populate the sockets so that the memory capacity is spread as equally
as possible between Channel A and Channel B.
5. Push the module down into the socket, ensuring that the module is fully inserted and properly
seated. Make sure the latches are in the closed position (3).
6. Repeat steps 4 and 5 to install any additional modules.
7. Replace the access panel.
8. If the computer was on a stand, replace the stand.
9. Reconnect the power cord and turn on the computer.
10. Lock any security devices that were disengaged when the access panel was removed.
The computer should automatically recognize the additional memory the next time you turn on the
computer.
Installing Additional Memory 119