Dell XPS 14 (L401X, Late 2010) - Manual (Page 17)

Memory Module(s) 17
6 Remove the memory module from the memory-module connector.
Replacing the Memory Module(s)
CAUTION: If you need to install memory modules in two connectors, install a
memory module in the connector labeled "DIMM A" before you install a memory
module in the connector labeled "DIMM B".
1 Follow the instructions in "Before You Begin" on page 9.
2 Align the notch in the memory module with the tab in the memory-
module connector.
1 memory-module connector 2 securing clips (2)
3 memory module
3
2
1