IBM 7063-CR2 Manual page 38

Figure 23. Removing the memory DIMM
5. Insert the memory DIMM.
a) Grasp the memory DIMM along its edges and align it with the slot on the system backplane.
Attention: Memory is keyed to prevent it from being installed incorrectly. Note the location
of the key tab within the memory connector before you attempt to install it.
b) Press firmly on each side of the memory DIMM until the locking tab locks in place with an audible
click.
24 Power Systems: Servicing the IBM Power Systems HMC (7063-CR2)