Dell Alienware Area 51 R2 (Late 2014) - Manual (Page 65)

2 Insert the memory module into the memory-module connector until the
memory module snaps into position and the securing clips lock in place.
NOTE: If you do not hear the click, remove the memory module and
reinstall it.
1 memory module 2 memory-module slot
3 notch
Post-requisites
1 Remove both the left and right side-panels. See “ Removing the Side
Panels ”.
2 Replace the stability foot .
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