Acer Altos R500 User Manual page 65

Note:
If you slip in a DIMM but it does not completely fit, you may have
inserted it the wrong way. Reverse the orientation of the DIMM.
Reconfiguring the system memory
The system automatically detects the amount of memory installed.
Run Setup to view the new value for total system memory and make a
note of it.
The DIMM socket is slotted to ensure proper installation.
55