Apple Mac Pro (Early 2009) - Manual (Page 48)

48 Chapter 3 Making a Good Thing Better
5 Open the ejectors on DIMM slots 1, 2, and 3 and push them out to the sides. Then
remove the DIMMs from the slots.
6 Install the DIMMs by aligning them in the DIMM slots and pushing both ends of the
DIMM down until the tabs are vertical and the ejectors snap into place.
NOTICE: To avoid damaging the DIMM, hold it by the corners and don’t touch the
gold connectors or other components.
Ejectors Notch Connectors