Dell OptiPlex GX1 Reference And Installation Manual page 109

You must use up to 15 pounds of force to disengage the SEC cartridge from the
connector.
SEC cartridge
tabbed guide-bracket
assembly
Press the SEC release latches outward until they snap into position. Orient the
assembly with the heat sink facing toward the right (as you face the front of the
chassis), and press the SEC firmly into its connector until it is fully seated. You
must use up to 25 pounds of force to fully seat the SEC cartridge/heat sink
assembly in the connector.
heat sink
tabs (2)
connector
Installing System Board Options 6-13