Compaq 159715-002 - Deskpro EN - DT 6650 Model 10000 Configuration Manual page 74

4. Open both latches of the memory module socket 1, and
insert the memory module into the socket 2.
Begin by installing a module into the socket nearest the
preinstalled module, and install the modules following the
numerical order of the sockets.
A memory module can be installed in only one way. Match
the notch on the module with the tab on the memory
socket. Push the module down into the socket, ensuring
that the module is fully inserted and properly seated 3.
Installing a RIMM and CRIMMs
All memory module sockets must be filled, either with a
RIMM or with a CRIMM.
4-14 Upgrading the Compaq Deskpro EN Series, Desktop Model