Dell Precision T7400 (Late 2007) - Manual (Page 210)

210 Adding and Replacing Parts
5 Disconnect any cables connected to the card.
6 Press down the tab on the top of the card retainer at the appropriate card
slot and pivot the card retainer back through the chassis wall.
1 graphics card bridge (not present
on some dual-graphics
configurations)
2 power connectors (2)
3 dual-PCI Express graphics cards
1
3
2