Dell XPS 15 (L501X, Late 2010) - Manual (Page 18)

18 Memory Module(s)
5 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 lower connector before you install a memory module in the
upper connector.
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 securing clip 2 memory-module connector
3 memory-module
2
3
1