Apple Mac Pro (Early 2009) - Manual (Page 70)

70 Chapter 3 Making a Good Thing Better
To install a PCI Express card:
1 Open your Mac Pro and remove the side panel following the instructions that begin on
page 37.
2 Unscrew the captive screws in the PCI bracket and remove the bracket.
3 Remove the port access cover from the slot in which you plan to install the card.
WARNING: To avoid damaging internal components or the components you want to
install, always turn off and then unplug your Mac Pro. Do not attempt to install items
while it is plugged in. Let your Mac Pro cool down for 5 to 10 minutes before you
touch the internal components, which may be very hot.
Port access cover
PCI bracket