Dell XPS 730 (Late 2008) - Manual (Page 27)

Replacing Memory Module(s) 25
Dell XPS 730X:
7 Align the notch on the bottom of the module with the tab in the
connector.
CAUTION: To avoid damage to the memory module, press the module straight
down into the connector while you apply equal force to each end of the module.
8 Insert the module into the connector until the module snaps into position.
1 cutouts (2) 2 memory module
3 notch 4 tab
3
2
1
4